You might benefit from reading thru this thread.
It looks to me that you need to find some way, in PMS or the clients, to disable hardware transcoding. It looks like they are still working thru issues with transcoding with newer gen Intel CPU/GPU. Kinda disappointing if you have a newer Intel chip and Plex isn’t up to speed yet with the drivers.
Addendum: Also, in Transcoding, disable (uncheck) “Use hardware acceleration when available.”
