I'm still getting the "passive AI bug" in a couple of situations. One was a seige battle (with me defending) where the AI would do nothing until engaged in melee. The second was a defensive battle where I wiped out the "reinforcement" army before turning towards the main army. It just sat there for a long time (I put it on 3x speed) and they only jumped into action when I poked them with a small melee. It's not a huge problem as I can just charge a unit with cav and then retreat with minimal losses and the battle plays out as normal.

Also, I get a lot of infantry charges that don't work very well, the whole unit splits up and a few members from the front rank shuffle up to the enemy. Then the rest of the unit spends the next couple of minutes slowly strolling over to the combat, by which time they're dead or the battle is decided! This seems to happen most in flanking attacks or when only a few of the unit are in combat, the rest don't seem to want to know and just sit there laughing at their dying comrads!