Symptom:

stp_io process abnormally restarts following an ifmgr abnormal restart. The traceback matches that in the DDTS.

In some cases (e.g. high scale, RP switchover), the process restart may not be quick enough to prevent protocol timeouts so there is some risk of a short period of network loops and/or traffic loss.

Conditions:

This issue is only seen when an STP interface registration attempt happens at the same time as ifmgr is unavailable (e.g. due to ifmgr restarting).