Thank you @anon5074910 for reporting and linking other similar threads here. This is a Web 4.121.1 and Desktop 1.84.1 only issue. As you mentioned in another thread you can work around this by using older versions of these apps.
The Desktop app installs usually have up to the last 3 versions in the local app data locations.
Windows - %LOCALAPPDATA%\Plex\cache\updates
MacOS - ~/Library/Caches/Plex/updates
For Web, you would need to use the bundled Web app on your PMS. http://localhost:32400/webor http://IP-ADDRESS:PORT/web depending on where you PMS is located.
The issue’s root cause has been found and fixed. The fix is already in the release pipeline. I’m not sure when this fix will go out. With this being the holidays, I’m very uncertain when this will get out. Keep an eye out for any activity in the Announcements area for Web and Desktop.
