Was waiting for a TMM match in the client and had it minimised while I was waiting. A match was found, and when I clicked on the client (to restore the window) it said I needed to login - i.e. it looked like it had timed me out and logged me out.
Not sure if this is intentional (in which case I'd suggest removing the auto-logout logic, since it's incredibly frustrating to wait ages for a match and then be unable to join it due to being auto-logged out), a bug, or some localised setting I need to change
Logged out of client while waiting for a match
M27AI developer; Devlog and more general AI development guide:
https://forum.faforever.com/topic/2373/ai-development-guide-and-m27ai-v70-devlog