This is pretty much always caused by albums which are either
- missing an AlbumArtist tag
- have more than one name as AlbumArtist [Plex cannot deal with collaborations]
- are stored within the same Artist folder (i.e. stored on disk) than an album with a deviating AlbumArtist
The only cure is to remove both the misattributed albums and those attributed to the other AlbumArtist and perform the Plex Dance.
So, in your case, “dance” both Ella and Count – after ensuring that all the points above are avoided.
