I found what is bug exactly. (in CS:GO)
It happened only terrorlist bots. they looking each other. and sometimes attack to his teammates.
Edit: I found more bug. i coded like this.
public Action OnShouldBotAttackPlayer(bot, player, &bool:result)
result = true;
they shoot each other. but bot terrorlists can kill each other. even though i set mp_friendlyfire convar to 0.