I always have my timer switched off in my games. This is particularly so important when assaulting large cities with a number of defenders, oh pointy-headed one.

I also try and use missile troops to kill off any defenders in the square. But, this can be pretty ineffective if the defenders are Warlord Cav, so sending in the ol' infantry is usually what I end up trying.

That is when this strange anomaly seems to cost me more casualties than I should have suffered. I simply can't get my troops to charge onto the square where the charge bonus can be very useful.