The FAQ suggests that NFS is problematic for concurrent access:
> But use caution: this locking mechanism might not work correctly if the database file is kept on an NFS filesystem. This is because fcntl() file locking is broken on many NFS implementations. You should avoid putting SQLite database files on NFS if multiple processes might try to access the file at the same time.
Oh yeah, I read all that after I started seeing problems, I know I'm in the wrong here. It works just good enough that I haven't addressed it yet (I just kick over the process when things get weird, and the db usually recovers just fine).
Can't remember where did I read this now but about a year ago I have found material saying that sqlite3 over NFS is a very bad idea and even though it's supported it's also strongly advised against as a use-case.
It's....not great.