.90 campaign - Kraxis came out of nowhere and took over my capital..
as though it had no defenders. My units were kicked out and placed next to the city. There isn't even a pop-up message saying that my city was captured! The save is from the turn before this occurs (also included the debug.err). I've reloaded the save and it happens each time so hopefully it will help you find the bug.
https://www.dropbox.com/sh/1g5j9yjt6w32a1f/CYVk2YK6-E
Edit - the previousautosave file is now the turn after it happens. Added a file "test" which is now the turn before it happens.