tl;dr: Tailscale spent six months chasing intermittent SQLite database corruption across their control plane shards, working with SQLite's core developers to eventually identify a 16-year-old data race between checkpoints and write transactions (dubbed the "WAL-Reset bug"). Their aggressive manual checkpointing—an unusual but supported configuration—made them uniquely likely to trigger it. The fix shipped in SQLite 3.51.3, and Tailscale later confirmed via instrumentation that the race condition was indeed occurring in production.