Hello, don't think I should be posting here, but can't post in the bug tracker (new user).
I was talking to Sierra in Girdershade (to deliver the naughty nightware mostly, and pick up the Quantum quest) and found her dialogue (changed by TTW no speech checks) has repeatable options that grant XP, also one is labeled "Charisma 25".
Sorry for the quality, I had to take these from my phone because I have disabled the overlay.