diff --git a/src/jrd/vio.cpp b/src/jrd/vio.cpp
index 78a3a7f5435..67c74a6dcb0 100644
--- a/src/jrd/vio.cpp
+++ b/src/jrd/vio.cpp
@@ -6557,6 +6557,8 @@ static PrepareResult prepare_update(thread_db* tdbb, jrd_tra* transaction, TraNu
 
 	if (new_rpb)
 	{
+		new_rpb->rpb_flags &= ~rpb_delta;
+
 		// If both descriptors share the same record, there cannot be any difference.
 		// This trick is used by VIO_writelock(), but can be a regular practice as well.
 		if (new_rpb->rpb_address == temp->rpb_address)