Here's a bug I haven't found mentioned (yet). Not sure if it is a bug or just a weird game thing but anyway. I'm posting it in multiplayer since that's what it happened in; but it may happen in single player too.
A lot of times when I'm wandering around the map and I come across another 'stone thrower' or 'brute' or whatever, I'll click to attack them and it'll say 'Does this mean WAR (against whoever)?' and click 'yes' and then nothing will happen. They'll just stand there. Now I do understand that this could be an accurate depiction of the brain capacity of early homo sapiens, but it's a bit weird. I have to click about three or four times before they'll attack.
On the times when they don't attack, the enemy flag flashes to my flag very briefly.