Indeed. Everyone who uses sqlite will get burnt by this one day and spend a lot of time chasing down errant write-upgraded transactions that cling on for a little bit longer than intended.

SQLite has its quirks, but in this particular case all you need is set PRAGMA busy_timeout=<a few seconds> and the problem is solved; and if you google it, it's widely known issue with described (this) solution.

It's just weird that it's set to 0 by default rather than something resonable like 3000 or 5000 ms.