The Plex Dance should clear that info out of the database.
Are you Plex Dancing just Season 5?
If so, Plex Dance the entire show.
Also, when you move the show back, only add Season 5. Make sure it is correct. Then add the other seasons. This just makes troubleshooting a bit faster, since Plex does not have to process the entire series, just a few episodes.
FYI, on cleaning bundles, you do that at the server level, not the library level. Choose More >, then your server, not the library.
Regarding freezing, use Plex Web, https://app.plex.tv/desktop/, instead of Plex for Windows. Plex Web should work w/o issue for adding shows, etc.
Plex for Windows should work, but on some PCs it has problems with stuttering, freezing, etc.
