I purchased lifetime premiere a few months ago and have yet to successfully play back media using the Emby Theater app without the "unlock this feature with an active Emby Premiere subscription" pop up. I do have the gold coin on the front page of the admin page on a web browser and have access to the other Premiere features through the standard web browser. I tried multiple computers, and clean installs of Emby Theater.
-On the side note. Every few logins using a typical computer web browser (tried multiple), I get the annoying Emby Premiere ad on my homescreen.
I tried to sign into the theater app using Emby Connect, and my Emby user account with no change.