Jaheria has this weird glitch where the world treats her as a separate ally even in my party, mostly to my detriment. When an encounter happens, she doesn't join it till I have her manually attack someone. Several spells don't work because they don't counter her as a companion, like area of effect heals. In the guildhall, she made the entire room hostile during the nine fingers vs zhenteriam battle, and I had to make her run out and come back in after, and she didn't attack anyone, just iced the floor. I've done all the quests related to her, I thought that would promote her to full companion, but nope.
I can't imagine this is intentional because of how much stuff this breaks that people would obviously have her around for. I know she and minsc are kinda different from the rest of the companions, but they are basically full companions in every other way, but for some reason the game just doesn't recognize her as one.
