Quick answer: Bug retrospectives once a month surface patterns triage can't see week-to-week. The exercise builds organizational learning.
What you fix individually accumulates; reflecting reveals what to fix systemically.
One hour
End of each month. QA + engineering lead. Walk the closed bugs.
Group by category
Concurrency bugs, UI bugs, performance regressions. Patterns tell you about your systems.
Decide systemic actions
Pattern of concurrency bugs: add static analysis. Pattern of UI bugs: usability test. Actions per pattern.
Track follow-ups
Each systemic action assigned. Next month's retro checks: did it ship?
“Bug data is information about the system. The system improves with reflection.”
If you don't have time for monthly retros, run quarterly. The frequency matters less than the discipline.