Thanks again for all your help, Otto.
I’m still hoping the Plex developers will somehow see the need to address this issue before it is released to the public… because having to use a 3rd party app to remove some obscure field in the media file, then having to perform either the Plex Dance or manually delete all these collections is probably more than many users would bargain for 
So in summary, this is the problem as I see it:
- Plex fills the Collection field with the information taken from the media file itself.
- The field in the media file is “Album”, this can only be viewed and edited with a 3rd party program such as MP3TAG.
- Dragging down Local Media Assets below The Movie Database in Agents does not solve the issue. This is inconsistent with the way other fields in Plex behave, such as the Title. Dragging Local Media Assets to the top fills the Title with the local title information, dragging it below The Movie Database uses the information from TMDB. Collections should work the same.
- Even in the unlikely event that all the above is considered a feature and not a bug, there is still a “real” bug involved. Once added, it is impossible to get rid of this collection even if the local file is edited. The only exception is using the Plex Dance - or manually deleting the collection. However manually deleting the collection locks the field, which then rules out automatic updates from the correct source (TMDB)
Once this is released to the public, I foresee a huge amount of complaints of people seeing weird collections appear, seemingly from nowhere. This can easily be prevented if only the developers look into this a bit further.
