OK found the issue which was reported to the development team by @ChuckPa
Sep 17, 2021 13:09:05.247 [0x2fa38d48] ERROR - Couldn't copy file "/volume1/@appstore/Plex Media Server/Resources/com.plexapp.plugins.library.db" to "/volume1/Plex/Library/Application Support/Plex Media Server/Plug-in Support/Databases/tv.plex.providers.epg.cloud-56893486-a5e3-44a9-8080-5e2209a399e2.db": Invalid argument
This should now be fixed as from Plex Media Server 1.24.4.5081-e362dc1ee
Release Notice:
- (Linux) Initial server setup and certain filesystem operations could fail on certain Linux systems (#13027