diff --git a/cylc/flow/task_events_mgr.py b/cylc/flow/task_events_mgr.py
index 0f89d2122dd..646386fee18 100644
--- a/cylc/flow/task_events_mgr.py
+++ b/cylc/flow/task_events_mgr.py
@@ -927,7 +927,7 @@ def _process_message_check(
         # gets logged by itask state change anyway (and not manual poll)
         if severity_lvl > DEBUG and flag != self.FLAG_POLLED and message in {
             self.EVENT_SUBMITTED, self.EVENT_STARTED, self.EVENT_SUCCEEDED,
-            self.EVENT_SUBMIT_FAILED, f'{FAIL_MESSAGE_PREFIX}ERR'
+            self.EVENT_SUBMIT_FAILED
         }:
             severity_lvl = DEBUG
         LOG.log(severity_lvl, f"[{itask}] {flag}{message}{timestamp}")