diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index a10bb89dcb..a9d3c22d7c 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -430,12 +430,10 @@ standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 		Gather	   *gather = makeNode(Gather);
 
 		/*
-		 * If there are any initPlans attached to the formerly-top plan node,
-		 * move them up to the Gather node; same as we do for Material node in
-		 * materialize_finished_plan.
+		 * Top plan must not have any initPlans, else it shouldn't have been
+		 * marked parallel-safe.
 		 */
-		gather->plan.initPlan = top_plan->initPlan;
-		top_plan->initPlan = NIL;
+		Assert(top_plan->initPlan == NIL);
 
 		gather->plan.targetlist = top_plan->targetlist;
 		gather->plan.qual = NIL;
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index a6ad28570a..15ffaa3707 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -1102,7 +1102,14 @@ set_subqueryscan_references(PlannerInfo *root,
 
 		result = plan->subplan;
 
-		/* We have to be sure we don't lose any initplans */
+		/*
+		 * We have to be sure we don't lose any initplans, so move any that
+		 * were attached to the parent plan to the child.  If we do move any,
+		 * the child is no longer parallel-safe.
+		 */
+		if (plan->scan.plan.initPlan)
+			result->parallel_safe = false;
+
 		result->initPlan = list_concat(plan->scan.plan.initPlan,
 									   result->initPlan);
 
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index b22519e69e..adada2a1b4 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -1879,7 +1879,7 @@ SS_identify_outer_params(PlannerInfo *root)
  * This is separate from SS_attach_initplans because we might conditionally
  * create more initPlans during create_plan(), depending on which Path we
  * select.  However, Paths that would generate such initPlans are expected
- * to have included their cost already.
+ * to have included their cost and parallel-safety effects already.
  */
 void
 SS_charge_for_initplans(PlannerInfo *root, RelOptInfo *final_rel)
@@ -1935,8 +1935,10 @@ SS_charge_for_initplans(PlannerInfo *root, RelOptInfo *final_rel)
  * (In principle the initPlans could go in any node at or above where they're
  * referenced; but there seems no reason to put them any lower than the
  * topmost node, so we don't bother to track exactly where they came from.)
- * We do not touch the plan node's cost; the initplans should have been
- * accounted for in path costing.
+ *
+ * We do not touch the plan node's cost or parallel_safe flag.  The initplans
+ * must have been accounted for in SS_charge_for_initplans, or by any later
+ * code that adds initplans via SS_make_initplan_from_plan.
  */
 void
 SS_attach_initplans(PlannerInfo *root, Plan *plan)
diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index aa8f2de72a..24a216e754 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -3093,7 +3093,7 @@ create_minmaxagg_path(PlannerInfo *root,
 	/* For now, assume we are above any joins, so no parameterization */
 	pathnode->path.param_info = NULL;
 	pathnode->path.parallel_aware = false;
-	/* A MinMaxAggPath implies use of subplans, so cannot be parallel-safe */
+	/* A MinMaxAggPath implies use of initplans, so cannot be parallel-safe */
 	pathnode->path.parallel_safe = false;
 	pathnode->path.parallel_workers = 0;
 	/* Result is one unordered row */