All of a sudden, when I go to Studio 2 through Photoshop, the changes I make there do not show up when I click on Accept and return to Photoshop.
Perhaps the problem lies with Photoshop. Their filter gallery no longer opens, and yes, I am in 8 bits RGB mode
Through trial and error found the culprit: something about the file I was working on blocked the filter gallery as well as Topaz Studio 2 filters. Solution: copy the last good layer to a new blank page and continue from there. All filters now working fine.