I had the same issue on my post-patch 5 playthrough. My character could not speak to any of the tieflings at the party in camp. I'd click on the party guest, my character would walk over and nothing would happen. I'm playing on PC and bought my game from Steam. I tried reloading but it didn't help. It also happened with Arabella in Act 2 but I was able to speak to her after long resting.