So wait, the reason it doesn't count towards the quest is because her kit doesn't match cannon? No offense to you personally, but that sounds like the dumbest thing I've ever heard. They can't just arbitrarily decide to change her kit but not actually change it like that. I don't believe that for a second.
It seems more likely to me that her healing immunity is coded differently because it's undispellable, and they didn't take that into account when they programmed the feats. Which is still terrible, of course.