Whenever I try to open Topaz Studio 2 in LR Classic, I see the interface for a fraction of a second and then it crashes. On a rare occasion, it will work. (And it works fine in PSCC.)
Jack, are you running on Windows or a Mac. On an ancient Mac portable it opens beautifully from LR Classic from a Mac running OSX 10.13.6. I have not tried it in PSCC.
Note, make sure you are running the latest version which is 2.1.0 - you may need to download the full installer from the Topaz Labs website.
Latest now 2.1.1 
