What is up with jaheira?

In the moonrise tower fight jaheira has been consistently useless, jumping right into the center of the room and getting surrounded making the use of aoe spells difficult, or purposefully running through a wall of fire or hunger of hadar while everyone else doesn't. Or my most recent play though turns into a panther and fucks off to Narnia, seriously she went invisible and that was It never saw her again until after the battle like thanks for the help.

Is her AI broken or something is she supposed to die this easily?