Hey
Sometimes the enemy won't fire when a task has been created by the commander, seems like they are stuck in safemode and ignoring everything. you can walk strait towards them and they do not engage you, they might throw a grenade at you when you are close.
I did a test to see if i could replicate ths with only cba and alive, i did 20 tests and this accured only once in the test. If this happend you must restart the mission, and it wil work again.