Yeah, in my case Jaheira automatically permanently left my party after I killed Ketheric every single time and I tried everything. But she then magically appeared in my camp and I can talk to her and shit and the game thinks she's part of my crew but when I ask her to join my party nothing happens. In other words I can't complete any of the quest lines involving her.
Its different to your situation but I think Jaheira as a character is completely bugged atm.
I´ve got exactly the same problem
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