AI Stopped Moving/Attacking

[MicheKRGD#1984]

Just started the game about a week ago. I've been progressing through the Russia campaign and thoroughly enjoying it. Obviously some of the missions are very difficult even on the 2nd lowest difficulty; however, it appears that around the Escape from Stalingrad mission, the AI has stopped doing anything except reacting. That mass of Soviet armor North of the German position did not so much as flinch the whole mission. Units returned fire when attacked but never moved. Same thing in Kharkov 43. I switched the difficulty to the middle level for Sicily and just clicked end turn over and over until the mission ended - again no enemy units moved. I have no mods or DLCs. I did change the difficulty level twice. Has anyone else encountered this issue? Is there a fix?

[KhanRaiderLeader]

Yes I have noticed the same behavior... lots of stationary targets..

[OldFocker]

Yes, and despite the rubbish Editor I've managed to modify some maps, but on some the enemy does nothing but return fire if approached. It's supposed to be attacking.