I saw this 
only once, I also decided at the 
very beginning of my time here (
2007-2008) just to play the game with maxed out buy points. As you know I generally only play 
Generated Campaigns against the AI. 
I know I didn't get beyond 
4-5 battles Cold War early 80'S timeline when this happened. I 
didn't put together the "
experience factor" until I saw 
Scorpio Rocks response above. 
But that makes perfectly good sense to me, since mathematically software would go negative in my "
simplistic" understanding of such things.
I would just end up deleting the Campaign anyway as it was a 
major PITA trying to manage 
ALL those units. I'm too "
hands on" of a player for that kind of headache.
Regards,
Pat
 Post Script:
Post Script: @ 2207-I just 
re-read your Post above again so, 
country wise it would've been 
either USA vs Soviet Union (Most likely.) or 
Germany vs Soviet Union (Much less likely.) as I was VERY MUCH in my "
Red Star/White Star" mood especially at that time.
Sorry I missed that bit of information but, a clue is a clue.
Pat