I’m can also confirm the forced transcode (even with latest beta version).
I’ve quickly tested on my iPhone 15 Pro, iPad Pro 11” M4 and iPad Pro 12.9” M1, and can playback Live TV without any crashing.
I’m not sure that what you are reporting is a common problem at this point, might pay if you can to include some logs or at least the hardware type and iOS versions to help others help, or for Plex team members if they see this thread.
Screen shot from Plex Dashboard (Plex Desktop, when playing Live TV from iPad).
