diff --git a/src/backend/distributed/planner/multi_router_planner.c b/src/backend/distributed/planner/multi_router_planner.c
index 3666544cb..e2386b84e 100644
--- a/src/backend/distributed/planner/multi_router_planner.c
+++ b/src/backend/distributed/planner/multi_router_planner.c
@@ -884,6 +884,15 @@ MultiTaskRouterSelectQuerySupported(Query *query)
 
 		Assert(subquery->commandType == CMD_SELECT);
 
+		/* pushing down rtes without relations yields (shardCount * expectedRows) */
+		if (subquery->rtable == NIL)
+		{
+			return DeferredError(ERRCODE_FEATURE_NOT_SUPPORTED,
+								 "Subqueries without relations are not allowed in "
+								 "INSERT ... SELECT queries",
+								 NULL, NULL);
+		}
+
 		/* pushing down limit per shard would yield wrong results */
 		if (subquery->limitCount != NULL)
 		{
diff --git a/src/test/regress/expected/multi_insert_select_non_pushable_queries.out b/src/test/regress/expected/multi_insert_select_non_pushable_queries.out
index e3c9c0d6b..ef0ec218b 100644
--- a/src/test/regress/expected/multi_insert_select_non_pushable_queries.out
+++ b/src/test/regress/expected/multi_insert_select_non_pushable_queries.out
@@ -660,3 +660,30 @@ FROM
   WHERE users_table.value_1 < 50;
 ERROR:  cannot perform distributed planning for the given modification
 DETAIL:  Select query cannot be pushed down to the worker.
+-- not supported since one of the queries doesn't have a relation
+INSERT INTO agg_results (user_id, agg_time, value_2_agg)
+SELECT
+    user_id,
+    user_lastseen,
+    array_length(event_array, 1)
+FROM (
+    SELECT
+        user_id,
+        max(u.time) as user_lastseen,
+        array_agg(event_type ORDER BY u.time) AS event_array
+    FROM (
+        SELECT user_id, time, value_3 as val_3
+        FROM users_table
+        WHERE
+        user_id >= 10 AND user_id <= 70 AND
+        users_table.value_1 > 10 AND users_table.value_1 < 12
+        ) u LEFT JOIN LATERAL (
+          SELECT event_type, time
+          FROM events_table, (SELECT 1 as x) as f
+          WHERE user_id = u.user_id AND
+          events_table.event_type > 10 AND events_table.event_type < 12
+        ) t ON true
+        GROUP BY user_id
+) AS shard_union
+ORDER BY user_lastseen DESC;
+ERROR:  Subqueries without relations are not allowed in INSERT ... SELECT queries
diff --git a/src/test/regress/sql/multi_insert_select_non_pushable_queries.sql b/src/test/regress/sql/multi_insert_select_non_pushable_queries.sql
index c7089903b..3982900a8 100644
--- a/src/test/regress/sql/multi_insert_select_non_pushable_queries.sql
+++ b/src/test/regress/sql/multi_insert_select_non_pushable_queries.sql
@@ -649,3 +649,30 @@ FROM
     ) temp 
   ON users_table.user_id = temp.user_id 
   WHERE users_table.value_1 < 50;
+
+-- not supported since one of the queries doesn't have a relation
+INSERT INTO agg_results (user_id, agg_time, value_2_agg)
+SELECT
+    user_id,
+    user_lastseen,
+    array_length(event_array, 1)
+FROM (
+    SELECT
+        user_id,
+        max(u.time) as user_lastseen,
+        array_agg(event_type ORDER BY u.time) AS event_array
+    FROM (
+        SELECT user_id, time, value_3 as val_3
+        FROM users_table
+        WHERE
+        user_id >= 10 AND user_id <= 70 AND
+        users_table.value_1 > 10 AND users_table.value_1 < 12
+        ) u LEFT JOIN LATERAL (
+          SELECT event_type, time
+          FROM events_table, (SELECT 1 as x) as f
+          WHERE user_id = u.user_id AND
+          events_table.event_type > 10 AND events_table.event_type < 12
+        ) t ON true
+        GROUP BY user_id
+) AS shard_union
+ORDER BY user_lastseen DESC;