That at least makes sense for her story though as we know she is written as being on the fence about Shar and Selune. Several points in the story show her heretical side, so it's not a surprise for the player if she were to go the Shar route if you don't have enough approval etc. But on the other hand, she expresses doubts on several occasions. That is proper foreshadowing. We as the player are not confused by this because it's handled properly and there isn't anything open to interpretation.
Its just not the case with her being into polyamory. If they wanted her to be that way they should have been more clear and had more foreshadowing. As it stands, it's written very poorly and looks shoehorned in. Writers cannot just plop something randomly in act 3 like that, that's not how proper writing is done.
