Quite frequently while playing skirmish vs 1 brutal AI, it fails to resign when it's defeated.
This is without doing a load of a saved game. In some cases the /cheat command was used to spawn some units earlier in the game maybe this has something to do with it, but regardless, the game should end as normal.
when victory is achived there is something similar to the following printed in the chat:
victory condition DEBUG
ally team 1 met conditions for defeat
team should resign