diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 5fa3d7323e..55538fa44c 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -677,7 +677,7 @@ AssertTXNLsnOrder(ReorderBuffer *rb)
 
 		/* Current initial LSN must be strictly higher than previous */
 		if (prev_first_lsn != InvalidXLogRecPtr)
-			Assert(prev_first_lsn < cur_txn->first_lsn);
+			Assert(prev_first_lsn <= cur_txn->first_lsn);
 
 		/* known-as-subtxn txns must not be listed */
 		Assert(!cur_txn->is_known_as_subxact);
@@ -778,9 +778,6 @@ ReorderBufferAssignChild(ReorderBuffer *rb, TransactionId xid,
 	txn = ReorderBufferTXNByXid(rb, xid, true, &new_top, lsn, true);
 	subtxn = ReorderBufferTXNByXid(rb, subxid, true, &new_sub, lsn, false);
 
-	if (new_top && !new_sub)
-		elog(ERROR, "subtransaction logged without previous top-level txn record");
-
 	if (!new_sub)
 	{
 		if (subtxn->is_known_as_subxact)
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
index dc64b1e0c2..c8b1fcd96c 100644
--- a/src/backend/replication/logical/snapbuild.c
+++ b/src/backend/replication/logical/snapbuild.c
@@ -772,6 +772,10 @@ SnapBuildProcessNewCid(SnapBuild *builder, TransactionId xid,
 {
 	CommandId	cid;
 
+	if (SnapBuildCurrentState(builder) < SNAPBUILD_FULL_SNAPSHOT &&
+		xlrec->top_xid != xid)
+		ReorderBufferAssignChild(builder->reorder, xlrec->top_xid, xid, lsn);
+
 	/*
 	 * we only log new_cid's if a catalog tuple was modified, so mark the
 	 * transaction as containing catalog modifications