I think this might be relevant.
I just remembered having similar issues after ee update & this fixed it for me.
…realistically though half the time I have issues after an update I kinda just save config & reinstall and 75% of the time it is fixed. Maybe also an option.
After those steps, I think some folks also had luck after stopping plex, removing gpu, starting it, stopping it, and then readding gpu. At least from a couple of posts I remember reading.