diff --git a/test/functional/test_framework/messages.py b/test/functional/test_framework/messages.py
index befb56a355d9ff..16bfe4c5a570ae 100755
--- a/test/functional/test_framework/messages.py
+++ b/test/functional/test_framework/messages.py
@@ -1592,7 +1592,7 @@ def __init__(self, idx, owner_addr, operator_pk, voting_addr, ipport, payout_add
         self.operator_sk = operator_sk
         self.proTx = None
         self.collateral = None
-        self.nullifier = None
+        self.nullifier = "%064x" % 0 if transparent else None
         self.transparent = transparent
 
     def revoked(self):