The Ordo Warbringer is a quest in Kun-Lai Summit, where you need to slay Warbringer after the fire shield which closes the entrance to his cave is shut down.
Hunter, when doing this quest, has a problem with a pet (maybe the same is for any other pet class): pet cannot enter the cave by the attack command or following the hunter, instead it stays at the entrance where the shield previously was. As a result, you need to pull this foe out of his cave, where the pet is able to attack him.
I suppose that the passability for the pet is not changed after shutting down the fire shield: pet stops thinking that shield is still here. Not a critical bug, but very unpleasant.