Who's killed the Amazon Fire TV Plex app?

My parents use the Amazon Fire TV stick to access my Plex content. Or at least they used to until the last upgrade where the UI has been revamped (which looks really bad) and all videos are stuttering making them unwatchable.

Everyone else (including me) using Plex on platforms other than the Amazon app including me are absolutely fine.

Please tell me this was a bad joke and it will be rolled back or fixed very soon?

The interface is not just bad-looking, it’s unusable. Only a few letters of titles are shown, and for TV episodes, there isn’t even enough shown on some with long titles after clicking on them. No way at all to see what the program is without playing it. It’s a disaster.
The thing that saves the Roku interface (which is also bad) is that the complete title of a video is always shown at the bottom of the screen after clicking on it. This would make the FireTV app at least usable.

I see the same issue. I have the first generation Fire TV Stick and prior to the Fire TV UI revamp, the streaming was working just fine. After the UI update, I noticed the stuttering as well. At first I thought it was the plex server, but the same videos work fine on 1st Gen chromecast on the same TV.