@Thaddy
By any chance: In trunk, are you using sqlite_open_v2 for InternalConnect?
I‘ve looked through the sourcecode, and found sqlite_open being used, and the docs for sqlite say, in that case sqlite is run with compiletime-options regarding multiple threads.
The default compile-options for distro-binaries is mode 1 (Serialized?), so right now i don‘t have a clue if it‘s my sqlite-lib being in singlethread-mode, or what you mentioned.
I‘m going to setup a small test, if the error occurs in a naked, stripped down, code