I have verified the issue is occurring on all/every new installation of Plex App on FireTV. I was able to cast to my Office & Bedroom FireTV apps (but not the new Livingroom FireCube.) I reset the Office to factory settings, installed the Plex App and cannot cast to it. It no longer shows in my MediaContainers XML call.
Seems older installations of the Plex App enabled the casting and registered as a player Something has changed in newer FireTV Plex App versions that are failing to register as a player.
This is replicatable 100% of the time on the current app version.
