In my first playthrough he was able to talk to Raphael outside of the Gauntlet of Shar. This time Raphael just left without ever giving Astarion a chance to ask any questions. So, I reloaded a save, did the whole House of Healing fight again, made sure to have Astarion selected when we approached the Gauntlet, and it auto switched to my character when the conversation started and he left again. Have they changed this sequence? Is it bugged? Do only certain dialogue choices give you a chance to barter?
I remember Astarion speaking up at that point even if my Tav was doing the talking. Astarion doesn’t have to be that main talker at that point.