I'd follow-up with questions on how you debugged that, how you'd do it now, what tooling you were missing, the testing strategy that led to this... I'd say it can be pretty interesting

you totally got it btw -- because questions should be conversation starters, not just "question -> answer" ad infinitum.

when i ask about a bug, i just want to know how you go debugging, understanding logs, dealing with other frustrated developers... you know, how you deal with things in a day-to-day basis.