I noticed that, since b27, the ai's in campaign mode don't help if an allied player is in the same map. EVERYONE was trying to take an unexplored area and my allied friend did nothing. He just stood there, useless. Didn't even try to order units. It seems to be that this ALWAYS happens if at least one human ally is one the same team color (I, II, III, IV). The other 2 ai brains both seemed to be cooperating.