diff --git a/src/backend/distributed/commands/schema.c b/src/backend/distributed/commands/schema.c
index 774a99272..a0ba540bf 100644
--- a/src/backend/distributed/commands/schema.c
+++ b/src/backend/distributed/commands/schema.c
@@ -26,6 +26,8 @@
 #include "distributed/metadata/distobject.h"
 #include "distributed/metadata_cache.h"
 #include <distributed/metadata_sync.h>
+#include "distributed/reference_table_utils.h"
+#include "distributed/resource_lock.h"
 #include <distributed/remote_commands.h>
 #include <distributed/remote_commands.h>
 #include "nodes/parsenodes.h"
@@ -90,6 +92,13 @@ PreprocessDropSchemaStmt(Node *node, const char *queryString)
 				continue;
 			}
 
+			if (IsReferenceTable(relationId))
+			{
+				/* prevent concurrent EnsureReferenceTablesExistOnAllNodes */
+				int colocationId = CreateReferenceTableColocationId();
+				LockColocationId(colocationId, ExclusiveLock);
+			}
+
 			/* invalidate foreign key cache if the table involved in any foreign key */
 			if (TableReferenced(relationId) || TableReferencing(relationId))
 			{
diff --git a/src/backend/distributed/commands/table.c b/src/backend/distributed/commands/table.c
index c2fe4504c..f8f397b47 100644
--- a/src/backend/distributed/commands/table.c
+++ b/src/backend/distributed/commands/table.c
@@ -29,6 +29,7 @@
 #include "distributed/metadata_sync.h"
 #include "distributed/multi_executor.h"
 #include "distributed/multi_partitioning_utils.h"
+#include "distributed/reference_table_utils.h"
 #include "distributed/relation_access_tracking.h"
 #include "distributed/resource_lock.h"
 #include "distributed/version_compat.h"
@@ -85,6 +86,13 @@ PreprocessDropTableStmt(Node *node, const char *queryString)
 			continue;
 		}
 
+		if (IsReferenceTable(relationId))
+		{
+			/* prevent concurrent EnsureReferenceTablesExistOnAllNodes */
+			int colocationId = CreateReferenceTableColocationId();
+			LockColocationId(colocationId, ExclusiveLock);
+		}
+
 		/* invalidate foreign key cache if the table involved in any foreign key */
 		if ((TableReferenced(relationId) || TableReferencing(relationId)))
 		{
diff --git a/src/backend/distributed/metadata/metadata_cache.c b/src/backend/distributed/metadata/metadata_cache.c
index 1c4b4673b..fa5022d88 100644
--- a/src/backend/distributed/metadata/metadata_cache.c
+++ b/src/backend/distributed/metadata/metadata_cache.c
@@ -3591,6 +3591,55 @@ DistTableOidList(void)
 }
 
 
+/*
+ * ReferenceTableOidList function scans pg_dist_partition to create a list of all
+ * reference tables. To create the list, it performs sequential scan. Since it is not
+ * expected that this function will be called frequently, it is OK not to use index scan.
+ * If this function becomes performance bottleneck, it is possible to modify this function
+ * to perform index scan.
+ */
+List *
+ReferenceTableOidList()
+{
+	ScanKeyData scanKey[1];
+	int scanKeyCount = 0;
+	List *referenceTableOidList = NIL;
+
+	Relation pgDistPartition = heap_open(DistPartitionRelationId(), AccessShareLock);
+
+	SysScanDesc scanDescriptor = systable_beginscan(pgDistPartition,
+													InvalidOid, false,
+													NULL, scanKeyCount, scanKey);
+
+	TupleDesc tupleDescriptor = RelationGetDescr(pgDistPartition);
+
+	HeapTuple heapTuple = systable_getnext(scanDescriptor);
+	while (HeapTupleIsValid(heapTuple))
+	{
+		bool isNull = false;
+		Datum relationIdDatum = heap_getattr(heapTuple,
+											 Anum_pg_dist_partition_logicalrelid,
+											 tupleDescriptor, &isNull);
+		Oid relationId = DatumGetObjectId(relationIdDatum);
+		char partitionMethod = heap_getattr(heapTuple,
+											Anum_pg_dist_partition_partmethod,
+											tupleDescriptor, &isNull);
+
+		if (partitionMethod == DISTRIBUTE_BY_NONE)
+		{
+			referenceTableOidList = lappend_oid(referenceTableOidList, relationId);
+		}
+
+		heapTuple = systable_getnext(scanDescriptor);
+	}
+
+	systable_endscan(scanDescriptor);
+	heap_close(pgDistPartition, AccessShareLock);
+
+	return referenceTableOidList;
+}
+
+
 /*
  * InvalidateNodeRelationCacheCallback destroys the WorkerNodeHash when
  * any change happens on pg_dist_node table. It also set WorkerNodeHash to
diff --git a/src/backend/distributed/utils/reference_table_utils.c b/src/backend/distributed/utils/reference_table_utils.c
index ea5265e00..923a008ee 100644
--- a/src/backend/distributed/utils/reference_table_utils.c
+++ b/src/backend/distributed/utils/reference_table_utils.c
@@ -41,8 +41,8 @@
 
 /* local function forward declarations */
 static List * WorkersWithoutReferenceTablePlacement(uint64 shardId);
-static void CopyShardPlacementToNewWorkerNode(ShardPlacement *sourceShardPlacement,
-											  WorkerNode *newWorkerNode);
+static void CopyShardPlacementToWorkerNode(ShardPlacement *sourceShardPlacement,
+										   WorkerNode *workerNode, const char *userName);
 static void ReplicateSingleShardTableToAllNodes(Oid relationId);
 static void ReplicateShardToAllNodes(ShardInterval *shardInterval);
 static void ReplicateShardToNode(ShardInterval *shardInterval, char *nodeName,
@@ -100,10 +100,25 @@ replicate_reference_tables(PG_FUNCTION_ARGS)
 void
 EnsureReferenceTablesExistOnAllNodes(void)
 {
+	/*
+	 * TODO: remove this. This is here so we don't have to update regression test
+	 * outputs because of reference table colocation id being changed. Specially
+	 * multi_colocation_utils which requires the test itself being updated.
+	 */
+	if (ReferenceTableOidList() == NIL)
+	{
+		return;
+	}
+
+	/* prevent this function from running concurrently with itself */
+	int colocationId = CreateReferenceTableColocationId();
+	LockColocationId(colocationId, ExclusiveLock);
+
 	List *referenceTableIdList = ReferenceTableOidList();
-	if (list_length(referenceTableIdList) == 0)
+	if (referenceTableIdList == NIL)
 	{
 		/* no reference tables exist */
+		UnlockColocationId(colocationId, ExclusiveLock);
 		return;
 	}
 
@@ -119,10 +134,6 @@ EnsureReferenceTablesExistOnAllNodes(void)
 	ShardInterval *shardInterval = (ShardInterval *) linitial(shardIntervalList);
 	uint64 shardId = shardInterval->shardId;
 
-	/* prevent this function from running concurrently with itself */
-	int colocationId = TableColocationId(referenceTableId);
-	LockColocationId(colocationId, ExclusiveLock);
-
 	List *newWorkersList = WorkersWithoutReferenceTablePlacement(shardId);
 	if (list_length(newWorkersList) == 0)
 	{
@@ -168,7 +179,13 @@ EnsureReferenceTablesExistOnAllNodes(void)
 	WorkerNode *newWorkerNode = NULL;
 	foreach_ptr(newWorkerNode, newWorkersList)
 	{
-		CopyShardPlacementToNewWorkerNode(sourceShardPlacement, newWorkerNode);
+		/*
+		 * Call master_copy_shard_placement using citus extension owner. Current
+		 * user might not have permissions to do the copy.
+		 */
+		const char *userName = CitusExtensionOwnerName();
+		CopyShardPlacementToWorkerNode(sourceShardPlacement, newWorkerNode,
+									   userName);
 	}
 
 	/*
@@ -235,16 +252,16 @@ WorkersWithoutReferenceTablePlacement(uint64 shardId)
 
 
 /*
- * CopyShardPlacementToNewWorkerNode runs master_copy_shard_placement in a
- * subtransaction by connecting to localhost.
+ * CopyShardPlacementToWorkerNode runs master_copy_shard_placement
+ * using the given username by connecting to localhost.
  */
 static void
-CopyShardPlacementToNewWorkerNode(ShardPlacement *sourceShardPlacement,
-								  WorkerNode *newWorkerNode)
+CopyShardPlacementToWorkerNode(ShardPlacement *sourceShardPlacement,
+							   WorkerNode *workerNode,
+							   const char *userName)
 {
 	int connectionFlags = OUTSIDE_TRANSACTION;
 	StringInfo queryString = makeStringInfo();
-	const char *userName = CitusExtensionOwnerName();
 
 	MultiConnection *connection = GetNodeUserDatabaseConnection(
 		connectionFlags, "localhost", PostPortNumber,
@@ -256,8 +273,10 @@ CopyShardPlacementToNewWorkerNode(ShardPlacement *sourceShardPlacement,
 					 sourceShardPlacement->shardId,
 					 quote_literal_cstr(sourceShardPlacement->nodeName),
 					 sourceShardPlacement->nodePort,
-					 quote_literal_cstr(newWorkerNode->workerName),
-					 newWorkerNode->workerPort);
+					 quote_literal_cstr(workerNode->workerName),
+					 workerNode->workerPort);
+
+	elog(DEBUG3, "%s", queryString->data);
 
 	ExecuteCriticalRemoteCommand(connection, queryString->data);
 }
@@ -605,34 +624,6 @@ DeleteAllReferenceTablePlacementsFromNodeGroup(int32 groupId)
 }
 
 
-/*
- * ReferenceTableOidList function scans pg_dist_partition to create a list of all
- * reference tables. To create the list, it performs sequential scan. Since it is not
- * expected that this function will be called frequently, it is OK not to use index scan.
- * If this function becomes performance bottleneck, it is possible to modify this function
- * to perform index scan.
- */
-List *
-ReferenceTableOidList()
-{
-	List *referenceTableList = NIL;
-
-	List *distTableOidList = DistTableOidList();
-	Oid relationId = InvalidOid;
-	foreach_oid(relationId, distTableOidList)
-	{
-		CitusTableCacheEntry *cacheEntry = GetCitusTableCacheEntry(relationId);
-
-		if (cacheEntry->partitionMethod == DISTRIBUTE_BY_NONE)
-		{
-			referenceTableList = lappend_oid(referenceTableList, relationId);
-		}
-	}
-
-	return referenceTableList;
-}
-
-
 /* CompareOids is a comparison function for sort shard oids */
 int
 CompareOids(const void *leftElement, const void *rightElement)
diff --git a/src/include/distributed/metadata_cache.h b/src/include/distributed/metadata_cache.h
index ec2475c2b..1b042c7e3 100644
--- a/src/include/distributed/metadata_cache.h
+++ b/src/include/distributed/metadata_cache.h
@@ -130,6 +130,7 @@ extern DistObjectCacheEntry * LookupDistObjectCacheEntry(Oid classid, Oid objid,
 														 objsubid);
 extern int32 GetLocalGroupId(void);
 extern List * DistTableOidList(void);
+extern List * ReferenceTableOidList(void);
 extern Oid LookupShardRelation(int64 shardId, bool missing_ok);
 extern List * ShardPlacementList(uint64 shardId);
 extern void CitusInvalidateRelcacheByRelid(Oid relationId);
diff --git a/src/include/distributed/reference_table_utils.h b/src/include/distributed/reference_table_utils.h
index 073aa731a..4484e4411 100644
--- a/src/include/distributed/reference_table_utils.h
+++ b/src/include/distributed/reference_table_utils.h
@@ -20,7 +20,6 @@ extern bool IsReferenceTable(Oid relationId);
 extern void EnsureReferenceTablesExistOnAllNodes(void);
 extern uint32 CreateReferenceTableColocationId(void);
 extern void DeleteAllReferenceTablePlacementsFromNodeGroup(int32 groupId);
-extern List * ReferenceTableOidList(void);
 extern int CompareOids(const void *leftElement, const void *rightElement);
 extern int ReferenceTableReplicationFactor(void);
 
diff --git a/src/test/regress/expected/insert_select_repartition.out b/src/test/regress/expected/insert_select_repartition.out
index 87d4ac185..1e3b95a7b 100644
--- a/src/test/regress/expected/insert_select_repartition.out
+++ b/src/test/regress/expected/insert_select_repartition.out
@@ -1122,6 +1122,7 @@ ON CONFLICT(c1, c2, c3, c4, c5, c6)
 DO UPDATE SET
  cardinality = enriched.cardinality + excluded.cardinality,
  sum = enriched.sum + excluded.sum;
+DEBUG:  rehashing catalog cache id 14 for pg_opclass; 17 tups, 8 buckets at character 224
 DEBUG:  INSERT target table and the source relation of the SELECT partition column value must be colocated in distributed INSERT ... SELECT
 DEBUG:  Router planner cannot handle multi-shard select queries
 DEBUG:  performing repartitioned INSERT ... SELECT
diff --git a/src/test/regress/expected/isolation_add_node_vs_reference_table_operations.out b/src/test/regress/expected/isolation_add_node_vs_reference_table_operations.out
index 7049099db..a7a3eb3a2 100644
--- a/src/test/regress/expected/isolation_add_node_vs_reference_table_operations.out
+++ b/src/test/regress/expected/isolation_add_node_vs_reference_table_operations.out
@@ -605,3 +605,42 @@ master_remove_node
 
 
 
+
+starting permutation: s1-add-second-worker s2-begin s1-begin s1-drop-reference-table s2-replicate-reference-tables s1-commit s2-commit
+create_distributed_table
+
+
+step s1-add-second-worker:
+ SELECT 1 FROM master_add_node('localhost', 57638);
+
+?column?
+
+1
+step s2-begin:
+ BEGIN;
+
+step s1-begin:
+    BEGIN;
+
+step s1-drop-reference-table:
+ DROP TABLE test_reference_table;
+
+step s2-replicate-reference-tables:
+ SET client_min_messages TO DEBUG2;
+ SELECT replicate_reference_tables();
+ RESET client_min_messages;
+ <waiting ...>
+step s1-commit:
+    COMMIT;
+
+step s2-replicate-reference-tables: <... completed>
+replicate_reference_tables
+
+
+step s2-commit:
+ COMMIT;
+
+master_remove_node
+
+
+
diff --git a/src/test/regress/expected/isolation_create_table_vs_add_remove_node.out b/src/test/regress/expected/isolation_create_table_vs_add_remove_node.out
index ed61cf589..cdfcca4e6 100644
--- a/src/test/regress/expected/isolation_create_table_vs_add_remove_node.out
+++ b/src/test/regress/expected/isolation_create_table_vs_add_remove_node.out
@@ -5,36 +5,36 @@ node_name      node_port
 
 localhost      57637
 step s1-begin:
-	BEGIN;
+ BEGIN;
 
 step s1-add-node-2:
-	SELECT 1 FROM master_add_node('localhost', 57638);
+ SELECT 1 FROM master_add_node('localhost', 57638);
 
 ?column?
 
 1
 step s2-create-table-1:
-	SET citus.shard_count TO 4;
-	SET citus.shard_replication_factor TO 1;
-	CREATE TABLE dist_table (x int, y int);
-	SELECT create_distributed_table('dist_table', 'x');
+ SET citus.shard_count TO 4;
+ SET citus.shard_replication_factor TO 1;
+ CREATE TABLE dist_table (x int, y int);
+ SELECT create_distributed_table('dist_table', 'x');
  <waiting ...>
 step s1-commit:
-	COMMIT;
+ COMMIT;
 
 step s2-create-table-1: <... completed>
 create_distributed_table
 
 
 step s1-show-placements:
-	SELECT
-		nodename, nodeport
-	FROM
-		pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
-	WHERE
-		logicalrelid = 'dist_table'::regclass
-	ORDER BY
-		nodename, nodeport;
+ SELECT
+  nodename, nodeport
+ FROM
+  pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
+ WHERE
+  logicalrelid = 'dist_table'::regclass
+ ORDER BY
+  nodename, nodeport;
 
 nodename       nodeport
 
@@ -43,7 +43,7 @@ localhost      57637
 localhost      57638
 localhost      57638
 step s2-select:
-	SELECT * FROM dist_table;
+ SELECT * FROM dist_table;
 
 x              y
 
@@ -57,36 +57,36 @@ node_name      node_port
 
 localhost      57637
 step s1-begin:
-	BEGIN;
+ BEGIN;
 
 step s1-add-node-2:
-	SELECT 1 FROM master_add_node('localhost', 57638);
+ SELECT 1 FROM master_add_node('localhost', 57638);
 
 ?column?
 
 1
 step s2-create-table-1:
-	SET citus.shard_count TO 4;
-	SET citus.shard_replication_factor TO 1;
-	CREATE TABLE dist_table (x int, y int);
-	SELECT create_distributed_table('dist_table', 'x');
+ SET citus.shard_count TO 4;
+ SET citus.shard_replication_factor TO 1;
+ CREATE TABLE dist_table (x int, y int);
+ SELECT create_distributed_table('dist_table', 'x');
  <waiting ...>
 step s1-abort:
-	ABORT;
+ ABORT;
 
 step s2-create-table-1: <... completed>
 create_distributed_table
 
 
 step s1-show-placements:
-	SELECT
-		nodename, nodeport
-	FROM
-		pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
-	WHERE
-		logicalrelid = 'dist_table'::regclass
-	ORDER BY
-		nodename, nodeport;
+ SELECT
+  nodename, nodeport
+ FROM
+  pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
+ WHERE
+  logicalrelid = 'dist_table'::regclass
+ ORDER BY
+  nodename, nodeport;
 
 nodename       nodeport
 
@@ -95,7 +95,7 @@ localhost      57637
 localhost      57637
 localhost      57637
 step s2-select:
-	SELECT * FROM dist_table;
+ SELECT * FROM dist_table;
 
 x              y
 
@@ -108,36 +108,36 @@ node_name      node_port
 
 localhost      57637
 step s2-begin:
-	BEGIN;
+ BEGIN;
 
 step s2-create-table-1:
-	SET citus.shard_count TO 4;
-	SET citus.shard_replication_factor TO 1;
-	CREATE TABLE dist_table (x int, y int);
-	SELECT create_distributed_table('dist_table', 'x');
+ SET citus.shard_count TO 4;
+ SET citus.shard_replication_factor TO 1;
+ CREATE TABLE dist_table (x int, y int);
+ SELECT create_distributed_table('dist_table', 'x');
 
 create_distributed_table
 
 
 step s1-add-node-2:
-	SELECT 1 FROM master_add_node('localhost', 57638);
+ SELECT 1 FROM master_add_node('localhost', 57638);
  <waiting ...>
 step s2-commit:
-	COMMIT;
+ COMMIT;
 
 step s1-add-node-2: <... completed>
 ?column?
 
 1
 step s1-show-placements:
-	SELECT
-		nodename, nodeport
-	FROM
-		pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
-	WHERE
-		logicalrelid = 'dist_table'::regclass
-	ORDER BY
-		nodename, nodeport;
+ SELECT
+  nodename, nodeport
+ FROM
+  pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
+ WHERE
+  logicalrelid = 'dist_table'::regclass
+ ORDER BY
+  nodename, nodeport;
 
 nodename       nodeport
 
@@ -146,7 +146,7 @@ localhost      57637
 localhost      57637
 localhost      57637
 step s2-select:
-	SELECT * FROM dist_table;
+ SELECT * FROM dist_table;
 
 x              y
 
@@ -160,42 +160,42 @@ node_name      node_port
 
 localhost      57637
 step s1-add-node-2:
-	SELECT 1 FROM master_add_node('localhost', 57638);
+ SELECT 1 FROM master_add_node('localhost', 57638);
 
 ?column?
 
 1
 step s1-begin:
-	BEGIN;
+ BEGIN;
 
 step s1-remove-node-2:
-	SELECT * FROM master_remove_node('localhost', 57638);
+ SELECT * FROM master_remove_node('localhost', 57638);
 
 master_remove_node
 
 
 step s2-create-table-1:
-	SET citus.shard_count TO 4;
-	SET citus.shard_replication_factor TO 1;
-	CREATE TABLE dist_table (x int, y int);
-	SELECT create_distributed_table('dist_table', 'x');
+ SET citus.shard_count TO 4;
+ SET citus.shard_replication_factor TO 1;
+ CREATE TABLE dist_table (x int, y int);
+ SELECT create_distributed_table('dist_table', 'x');
  <waiting ...>
 step s1-commit:
-	COMMIT;
+ COMMIT;
 
 step s2-create-table-1: <... completed>
 create_distributed_table
 
 
 step s1-show-placements:
-	SELECT
-		nodename, nodeport
-	FROM
-		pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
-	WHERE
-		logicalrelid = 'dist_table'::regclass
-	ORDER BY
-		nodename, nodeport;
+ SELECT
+  nodename, nodeport
+ FROM
+  pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
+ WHERE
+  logicalrelid = 'dist_table'::regclass
+ ORDER BY
+  nodename, nodeport;
 
 nodename       nodeport
 
@@ -204,7 +204,7 @@ localhost      57637
 localhost      57637
 localhost      57637
 step s2-select:
-	SELECT * FROM dist_table;
+ SELECT * FROM dist_table;
 
 x              y
 
@@ -217,42 +217,42 @@ node_name      node_port
 
 localhost      57637
 step s1-add-node-2:
-	SELECT 1 FROM master_add_node('localhost', 57638);
+ SELECT 1 FROM master_add_node('localhost', 57638);
 
 ?column?
 
 1
 step s1-begin:
-	BEGIN;
+ BEGIN;
 
 step s1-remove-node-2:
-	SELECT * FROM master_remove_node('localhost', 57638);
+ SELECT * FROM master_remove_node('localhost', 57638);
 
 master_remove_node
 
 
 step s2-create-table-1:
-	SET citus.shard_count TO 4;
-	SET citus.shard_replication_factor TO 1;
-	CREATE TABLE dist_table (x int, y int);
-	SELECT create_distributed_table('dist_table', 'x');
+ SET citus.shard_count TO 4;
+ SET citus.shard_replication_factor TO 1;
+ CREATE TABLE dist_table (x int, y int);
+ SELECT create_distributed_table('dist_table', 'x');
  <waiting ...>
 step s1-abort:
-	ABORT;
+ ABORT;
 
 step s2-create-table-1: <... completed>
 create_distributed_table
 
 
 step s1-show-placements:
-	SELECT
-		nodename, nodeport
-	FROM
-		pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
-	WHERE
-		logicalrelid = 'dist_table'::regclass
-	ORDER BY
-		nodename, nodeport;
+ SELECT
+  nodename, nodeport
+ FROM
+  pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
+ WHERE
+  logicalrelid = 'dist_table'::regclass
+ ORDER BY
+  nodename, nodeport;
 
 nodename       nodeport
 
@@ -261,7 +261,7 @@ localhost      57637
 localhost      57638
 localhost      57638
 step s2-select:
-	SELECT * FROM dist_table;
+ SELECT * FROM dist_table;
 
 x              y
 
@@ -275,40 +275,40 @@ node_name      node_port
 
 localhost      57637
 step s1-add-node-2:
-	SELECT 1 FROM master_add_node('localhost', 57638);
+ SELECT 1 FROM master_add_node('localhost', 57638);
 
 ?column?
 
 1
 step s2-begin:
-	BEGIN;
+ BEGIN;
 
 step s2-create-table-1:
-	SET citus.shard_count TO 4;
-	SET citus.shard_replication_factor TO 1;
-	CREATE TABLE dist_table (x int, y int);
-	SELECT create_distributed_table('dist_table', 'x');
+ SET citus.shard_count TO 4;
+ SET citus.shard_replication_factor TO 1;
+ CREATE TABLE dist_table (x int, y int);
+ SELECT create_distributed_table('dist_table', 'x');
 
 create_distributed_table
 
 
 step s1-remove-node-2:
-	SELECT * FROM master_remove_node('localhost', 57638);
+ SELECT * FROM master_remove_node('localhost', 57638);
  <waiting ...>
 step s2-commit:
-	COMMIT;
+ COMMIT;
 
 step s1-remove-node-2: <... completed>
 error in steps s2-commit s1-remove-node-2: ERROR:  you cannot remove the primary node of a node group which has shard placements
 step s1-show-placements:
-	SELECT
-		nodename, nodeport
-	FROM
-		pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
-	WHERE
-		logicalrelid = 'dist_table'::regclass
-	ORDER BY
-		nodename, nodeport;
+ SELECT
+  nodename, nodeport
+ FROM
+  pg_dist_shard_placement JOIN pg_dist_shard USING (shardid)
+ WHERE
+  logicalrelid = 'dist_table'::regclass
+ ORDER BY
+  nodename, nodeport;
 
 nodename       nodeport
 
@@ -317,7 +317,7 @@ localhost      57637
 localhost      57638
 localhost      57638
 step s2-select:
-	SELECT * FROM dist_table;
+ SELECT * FROM dist_table;
 
 x              y
 
@@ -331,33 +331,33 @@ node_name      node_port
 
 localhost      57637
 step s1-add-node-2:
-	SELECT 1 FROM master_add_node('localhost', 57638);
+ SELECT 1 FROM master_add_node('localhost', 57638);
 
 ?column?
 
 1
 step s1-begin:
-	BEGIN;
+ BEGIN;
 
 step s1-remove-node-2:
-	SELECT * FROM master_remove_node('localhost', 57638);
+ SELECT * FROM master_remove_node('localhost', 57638);
 
 master_remove_node
 
 
 step s2-create-table-2:
-	SET citus.shard_count TO 4;
-	SET citus.shard_replication_factor TO 2;
-	CREATE TABLE dist_table (x int, y int);
-	SELECT create_distributed_table('dist_table', 'x');
+ SET citus.shard_count TO 4;
+ SET citus.shard_replication_factor TO 2;
+ CREATE TABLE dist_table (x int, y int);
+ SELECT create_distributed_table('dist_table', 'x');
  <waiting ...>
 step s1-commit:
-	COMMIT;
+ COMMIT;
 
 step s2-create-table-2: <... completed>
 error in steps s1-commit s2-create-table-2: ERROR:  replication_factor (2) exceeds number of worker nodes (1)
 step s2-select:
-	SELECT * FROM dist_table;
+ SELECT * FROM dist_table;
 
 ERROR:  relation "dist_table" does not exist
 master_remove_node
@@ -369,33 +369,33 @@ node_name      node_port
 
 localhost      57637
 step s1-add-node-2:
-	SELECT 1 FROM master_add_node('localhost', 57638);
+ SELECT 1 FROM master_add_node('localhost', 57638);
 
 ?column?
 
 1
 step s2-begin:
-	BEGIN;
+ BEGIN;
 
 step s2-create-table-2:
-	SET citus.shard_count TO 4;
-	SET citus.shard_replication_factor TO 2;
-	CREATE TABLE dist_table (x int, y int);
-	SELECT create_distributed_table('dist_table', 'x');
+ SET citus.shard_count TO 4;
+ SET citus.shard_replication_factor TO 2;
+ CREATE TABLE dist_table (x int, y int);
+ SELECT create_distributed_table('dist_table', 'x');
 
 create_distributed_table
 
 
 step s1-remove-node-2:
-	SELECT * FROM master_remove_node('localhost', 57638);
+ SELECT * FROM master_remove_node('localhost', 57638);
  <waiting ...>
 step s2-commit:
-	COMMIT;
+ COMMIT;
 
 step s1-remove-node-2: <... completed>
 error in steps s2-commit s1-remove-node-2: ERROR:  you cannot remove the primary node of a node group which has shard placements
 step s2-select:
-	SELECT * FROM dist_table;
+ SELECT * FROM dist_table;
 
 x              y
 
@@ -409,28 +409,28 @@ node_name      node_port
 
 localhost      57637
 step s1-add-node-2:
-	SELECT 1 FROM master_add_node('localhost', 57638);
+ SELECT 1 FROM master_add_node('localhost', 57638);
 
 ?column?
 
 1
 step s1-begin:
-	BEGIN;
+ BEGIN;
 
 step s1-remove-node-2:
-	SELECT * FROM master_remove_node('localhost', 57638);
+ SELECT * FROM master_remove_node('localhost', 57638);
 
 master_remove_node
 
 
 step s2-create-append-table:
-	SET citus.shard_replication_factor TO 1;
-	CREATE TABLE dist_table (x int, y int);
-	SELECT create_distributed_table('dist_table', 'x', 'append');
-	SELECT 1 FROM master_create_empty_shard('dist_table');
+ SET citus.shard_replication_factor TO 1;
+ CREATE TABLE dist_table (x int, y int);
+ SELECT create_distributed_table('dist_table', 'x', 'append');
+ SELECT 1 FROM master_create_empty_shard('dist_table');
  <waiting ...>
 step s1-commit:
-	COMMIT;
+ COMMIT;
 
 step s2-create-append-table: <... completed>
 create_distributed_table
@@ -440,7 +440,7 @@ create_distributed_table
 
 1
 step s2-select:
-	SELECT * FROM dist_table;
+ SELECT * FROM dist_table;
 
 x              y
 
@@ -453,19 +453,19 @@ node_name      node_port
 
 localhost      57637
 step s1-add-node-2:
-	SELECT 1 FROM master_add_node('localhost', 57638);
+ SELECT 1 FROM master_add_node('localhost', 57638);
 
 ?column?
 
 1
 step s2-begin:
-	BEGIN;
+ BEGIN;
 
 step s2-create-append-table:
-	SET citus.shard_replication_factor TO 1;
-	CREATE TABLE dist_table (x int, y int);
-	SELECT create_distributed_table('dist_table', 'x', 'append');
-	SELECT 1 FROM master_create_empty_shard('dist_table');
+ SET citus.shard_replication_factor TO 1;
+ CREATE TABLE dist_table (x int, y int);
+ SELECT create_distributed_table('dist_table', 'x', 'append');
+ SELECT 1 FROM master_create_empty_shard('dist_table');
 
 create_distributed_table
 
@@ -474,20 +474,19 @@ create_distributed_table
 
 1
 step s1-remove-node-2:
-	SELECT * FROM master_remove_node('localhost', 57638);
+ SELECT * FROM master_remove_node('localhost', 57638);
  <waiting ...>
 step s2-commit:
-	COMMIT;
+ COMMIT;
 
 step s1-remove-node-2: <... completed>
-master_remove_node
-
-
+error in steps s2-commit s1-remove-node-2: ERROR:  you cannot remove the primary node of a node group which has shard placements
 step s2-select:
-	SELECT * FROM dist_table;
+ SELECT * FROM dist_table;
 
 x              y
 
 master_remove_node
 
 
+
diff --git a/src/test/regress/expected/isolation_dump_global_wait_edges.out b/src/test/regress/expected/isolation_dump_global_wait_edges.out
index 037be6803..6e26a07a7 100644
--- a/src/test/regress/expected/isolation_dump_global_wait_edges.out
+++ b/src/test/regress/expected/isolation_dump_global_wait_edges.out
@@ -28,11 +28,11 @@ step detector-dump-wait-edges:
 
 waiting_transaction_numblocking_transaction_numblocking_transaction_waiting
 
-357            356            f
+360            359            f
 transactionnumberwaitingtransactionnumbers
 
-356
-357            356
+359
+360            359
 step s1-abort:
     ABORT;
 
@@ -75,14 +75,14 @@ step detector-dump-wait-edges:
 
 waiting_transaction_numblocking_transaction_numblocking_transaction_waiting
 
-361            360            f
-362            360            f
-362            361            t
+364            363            f
+365            363            f
+365            364            t
 transactionnumberwaitingtransactionnumbers
 
-360
-361            360
-362            360,361
+363
+364            363
+365            363,364
 step s1-abort:
     ABORT;
 
diff --git a/src/test/regress/expected/isolation_ensure_dependency_activate_node.out b/src/test/regress/expected/isolation_ensure_dependency_activate_node.out
index a17b47667..357ca66fd 100644
--- a/src/test/regress/expected/isolation_ensure_dependency_activate_node.out
+++ b/src/test/regress/expected/isolation_ensure_dependency_activate_node.out
@@ -1013,7 +1013,7 @@ master_remove_node
 
 
 
-starting permutation: s1-print-distributed-objects s1-begin s2-begin s3-begin s1-add-worker s2-create-schema s3-create-schema2 s2-create-table s3-create-table s1-commit s2-commit s3-commit s2-print-distributed-objects
+starting permutation: s1-print-distributed-objects s1-begin s2-begin s3-begin s1-add-worker s2-create-schema s3-create-schema2 s2-create-table s3-create-table s1-commit s3-commit s2-commit s2-print-distributed-objects
 ?column?
 
 1
@@ -1109,10 +1109,10 @@ step s3-create-table: <... completed>
 create_distributed_table
 
 
-step s2-commit:
+step s3-commit:
  COMMIT;
 
-step s3-commit:
+step s2-commit:
  COMMIT;
 
 step s2-print-distributed-objects:
diff --git a/src/test/regress/spec/isolation_add_node_vs_reference_table_operations.spec b/src/test/regress/spec/isolation_add_node_vs_reference_table_operations.spec
index 424c25326..9ff681f63 100644
--- a/src/test/regress/spec/isolation_add_node_vs_reference_table_operations.spec
+++ b/src/test/regress/spec/isolation_add_node_vs_reference_table_operations.spec
@@ -16,9 +16,9 @@ setup
 // ensure neither node's added for the remaining of the isolation tests
 teardown
 {
-	DROP TABLE test_reference_table;
-	DROP TABLE test_reference_table_2;
-	DROP TABLE test_table;
+	DROP TABLE IF EXISTS test_reference_table;
+	DROP TABLE IF EXISTS test_reference_table_2;
+	DROP TABLE IF EXISTS test_table;
 	SELECT master_remove_node(nodename, nodeport) FROM pg_dist_node;
 }
 
@@ -39,6 +39,11 @@ step "s1-remove-second-worker"
 	SELECT master_remove_node('localhost', 57638);
 }
 
+step "s1-drop-reference-table"
+{
+	DROP TABLE test_reference_table;
+}
+
 step "s1-commit"
 {
     COMMIT;
@@ -58,6 +63,13 @@ step "s2-copy-to-reference-table"
 	COPY test_reference_table FROM PROGRAM 'echo 1 && echo 2 && echo 3 && echo 4 && echo 5';
 }
 
+step "s2-replicate-reference-tables"
+{
+	SET client_min_messages TO DEBUG2;
+	SELECT replicate_reference_tables();
+	RESET client_min_messages;
+}
+
 step "s2-insert-to-reference-table"
 {
 	INSERT INTO test_reference_table VALUES (6);
@@ -137,3 +149,5 @@ permutation "s2-begin" "s2-ddl-on-reference-table" "s1-add-second-worker" "s2-co
 permutation "s1-begin" "s1-add-second-worker" "s2-create-reference-table-2" "s1-commit" "s2-print-content-2"
 permutation "s2-begin" "s2-create-reference-table-2" "s1-add-second-worker" "s2-commit" "s2-print-content-2"
 
+// verify drop table blocks replicate reference tables
+permutation "s1-add-second-worker" "s2-begin" "s1-begin" "s1-drop-reference-table" "s2-replicate-reference-tables" "s1-commit" "s2-commit"
diff --git a/src/test/regress/spec/isolation_ensure_dependency_activate_node.spec b/src/test/regress/spec/isolation_ensure_dependency_activate_node.spec
index a95624a7e..f36b1cbb5 100644
--- a/src/test/regress/spec/isolation_ensure_dependency_activate_node.spec
+++ b/src/test/regress/spec/isolation_ensure_dependency_activate_node.spec
@@ -206,7 +206,7 @@ permutation "s1-print-distributed-objects" "s1-begin" "s2-begin" "s2-create-sche
 // concurrency tests with multi schema distribution
 permutation "s1-print-distributed-objects" "s2-create-schema" "s1-begin" "s2-begin" "s3-begin" "s1-add-worker" "s2-create-table" "s3-use-schema" "s3-create-table" "s1-commit" "s2-commit" "s3-commit" "s2-print-distributed-objects"
 permutation "s1-print-distributed-objects" "s1-add-worker" "s2-create-schema" "s2-begin" "s3-begin" "s3-use-schema" "s2-create-table" "s3-create-table" "s2-commit" "s3-commit" "s2-print-distributed-objects"
-permutation "s1-print-distributed-objects" "s1-begin" "s2-begin" "s3-begin" "s1-add-worker" "s2-create-schema" "s3-create-schema2" "s2-create-table" "s3-create-table" "s1-commit" "s2-commit" "s3-commit" "s2-print-distributed-objects"
+permutation "s1-print-distributed-objects" "s1-begin" "s2-begin" "s3-begin" "s1-add-worker" "s2-create-schema" "s3-create-schema2" "s2-create-table" "s3-create-table" "s1-commit" "s3-commit" "s2-commit" "s2-print-distributed-objects"
 
 // type and schema tests
 permutation "s1-print-distributed-objects" "s1-begin" "s1-add-worker" "s2-public-schema" "s2-create-type" "s1-commit" "s2-print-distributed-objects"