Totally feel for you bro. I can understand units staying where they were the turn prior, but when I see a stack move somewhere I didn't put them I'm like lolwut .___.
Played a world game but it was a 1V1 in EU with me and this other player. Player was about to throw a big stack into my cap (RC. This wasn't extra cities so don't judge me!
) and I has 30 units in the Ukraine all ready to retreat back into my cap. Next turn those 30 units are in between the cap of Ukraine and Lviv and the other player had taken my cap. Had my units gone to Moscow, I would have easily kept my country, had gotten reinforcements, and destroyed his stack.