Sorry, that is not what I meant.
Which folder has been added to the Plex library? You can verify this by editing the library.
It is important, that the library is pointed to the folder which holds all the AlbumArtist folders. Which in your case is the folder Lossless.
If you also have another folder which holds mp3 files and is named mp3, you will have to add this mp3 folder separately. In other words: adding the folder Musica instead would be wrong.
If your changes to the metadata are such, that the album has to switch into a different album artist, you sometimes have to perform the Plex Dance with the album. (although with music, you usually can omit step 4 of the Dance)
