Looks like it is just "pooping" or something. The coloring looks good, the tentacles are full, and it is eating. They go through cycles of inflate and deflate during the day. How often are you feeding? How long after the lights come on is this picture?
What is the flow like in that area? Try not feeding it for a few days and see what happens. Like mentioned above, it might be ready to split. It looks plenty healthy though. Do you have any before pictures?
IMO its your clown. I recently had to remove a clown from my tank because he was causing my bta's to close up. Is your clown agressive with your rbta?
Looks like it went higher. How long have you had it? I think it is just adjusting to the new location (and possibly higher flow). It is coming out, it is feeding, it is plump and nicely colored. I would just give it time. How old are your lights?