Thanks for the reply. I saw this as a potential answer in forums elsewhere. Unfortunately, this does not solve the issue. It seems the issue is the tap gesture itself. If you long press, highlighting occurs. If you do a quick, light tap, the button does not highlight.

I am also having the same issue. Subscriptions are stuck in "Waiting for review". I made the mistake by releasing my app thinking everything was good to go but now users will not be able to upgrade to my premium version. It's been 24 hours since my app was released to public. I guess I will give it another day before calling support.