Comment 3 for bug 721163

This is strange. I can't think of any likely causes, and I don't think any hooks are triggered by that RPC so it's unlikely to be a faulty plugin either. I think we need to see the bzr log from the server.

Oh! The error string matches an error raised by _chk_map_pyx._bytes_to_text_key. In bzr 2.3 that error message has been improved to give slightly more information, so it'd be worth upgrading the server to 2.3.