Fire TV Sync not working properly on Plex

Hello! I’ve been using the Hue Essentials App on my Phone and Watch for a while and I love it. Since I just got more Hue Lightstrips for my livingroom, I wanted to set up an entertainment zone to sync it via Hue Essentials.

I bought the addon and it seems to work (Most apps easily work with it), but It does not work with any movie. I know, that it can’t work with Netflix or similar due to the screenrecording restrictions. But since I mostly use Plex, I hoped it would work. On my Brother’s Chromecast with Google TV Plex seems to be the only thing that works perfectly so I was hoping it would be the same for Fire TV.

I can see that it works in the App iteslf. When I scroll through my Movies, it changes the colours depending on the Posters. But when the movie starts, all the lights turn off and stay off. When I pause or do anything that pops up the controls, all the lights light up at like 15%. So it seems to work in Plex, but not during movies. Is this a known issue? Is there something I can try to fix this?

Thanks a lot in advance!