Plex webUI Playback Error on refresh

potentially linked:

“There was an unexpected error during playback” on all media (MacOS v1.87.2.87-87488d5a) - Plex Players / Desktop Players - Plex Forum

even though the title says MacOS, this happens for me also. The workaround is in it (disable scanning). Not sure what the cause it, but most likely this is all the same issue.