diff --git a/direct/src/directutil/DistributedLargeBlobSenderAI.py b/direct/src/directutil/DistributedLargeBlobSenderAI.py
index b7809d9e40..dbb82a4ee9 100755
--- a/direct/src/directutil/DistributedLargeBlobSenderAI.py
+++ b/direct/src/directutil/DistributedLargeBlobSenderAI.py
@@ -65,4 +65,5 @@ class DistributedLargeBlobSenderAI(DistributedObjectAI.DistributedObjectAI):
 
     def setAck(self):
         DistributedLargeBlobSenderAI.notify.debug('setAck')
+        assert self.air.msgSender == self.targetAvId
         self.requestDelete()