Agreed, buggy companion, half baked and underdeveloped relationship arc. Most disappointing part of the game so far. And the trade off of having the other companions leave is not worth it with Minthara in her current state. It feels like Larian phoned it in with her or they just didn't have time to make her worthwhile as she was originally meant to be a one night stand not a full blown companion, just a hunch.
Ouch, is it really that bad? I am actually looking forward to playing Evil and recruiting her.
Such a shame.