diff --git a/blockchain-configs/testnet-prod/timer_flags.json b/blockchain-configs/testnet-prod/timer_flags.json
index 67c906f07..f985ef2a9 100644
--- a/blockchain-configs/testnet-prod/timer_flags.json
+++ b/blockchain-configs/testnet-prod/timer_flags.json
@@ -64,7 +64,7 @@
     "has_bandage": true
   },
   "update_tx_bytes_limit": {
-    "enabled_block": null,
+    "enabled_block": 3938200,
     "has_bandage": true
   }
 }