diff --git a/src/backend/distributed/planner/relation_restriction_equivalence.c b/src/backend/distributed/planner/relation_restriction_equivalence.c
index 5a6efe6e9..b558844ca 100644
--- a/src/backend/distributed/planner/relation_restriction_equivalence.c
+++ b/src/backend/distributed/planner/relation_restriction_equivalence.c
@@ -162,7 +162,7 @@ QueryContainsDistributionKeyEquality(PlannerRestrictionContext *plannerRestricti
 		return true;
 	}
 
-	if (ContainsUnionSubquery(originalQuery))
+	if (originalQuery->setOperations || ContainsUnionSubquery(originalQuery))
 	{
 		return SafeToPushdownUnionSubquery(plannerRestrictionContext);
 	}