Reopened tickets no longer locking to user

[inosek]

We're configured so, if a closed ticket is reopened, it will automatically lock to the previous owner.
However, this does not appear to be working, as we're seeing tickets that have had followups after closing, but they remain unlocked in the system.
Ticket owners are not receiving any notification that one of their closed tickets has reopened and requires follow up.

This has been working for years. I've ensured that "Ticket lock after followup" is set to Yes for every queue.
I vaguely recall there was something in Core:Ticket, but I'm not seeing anything and, AFAIK, there haven't been any changes to the system.

[zzz]

Did you check the ticket history for hints? You can also post a screenshot.

— Emin