I haven't been able to get 4K videos of any kind to stream via Plex to Google Cast. Is this is known issue? -Note, I'm obviously not talking about Chromecast devices that don't support 4K video but instead Google Cast devices that do.
Plex logs reports the video is playing, but I just get a black screen on the TV with a spinning wheel as if it's buffering. But no errors.
No issues casting 4K content to the same TV in other apps - just Plex. Also no issue direct playing the same 4K content with Nvidia Shield on the same TV.