[code_biologist]

I think there's room for a hybrid approach, not just fixing the bug a fuzz test found, but treating the fuzz test error as a bug in invariants (either inadequate or violated in a subtle way that's not caught) and addressing that underlying issue.

[jacquesm]

Yes, good point: often it is the assumptions themselves that were broken. So effectively you are debugging both the real system and the monitoring system.