Throughout the game you do several quests in which an NPC will assist you. Usually they're functional but almost every time they help you with a boss fight, about a quarter to halfway through the battle they sheathe their weapon and just stand there like idiots.
I have several characters in the Dominion and I can reproduce this virtually every time you fight Norian; about halfway through the battle, Ayrenn just puts her weapon up and stands there watching you die. Most recently it happened in the battle with Estre, in which Urcelmo, Raz, and the healer all quit at the same time. Needless to say the enemy NPCs rarely attack them after they quit. They're obviously there to ease the pressure of the bigger fights so it's frustrating to see them just stop like that.