This means that your library hasn’t been converted to use the new music code.
You can try to keep these settings, but they are not exactly supported anymore.
If you change them both to ‘Plex Music’, you will be using the new music support with muscibrainz.org as the main datasource.
However, I am pretty sure that this will create even more havoc with your existing folder organisation.
So I’d try another strategy first:
Populate the Track# meta tag of all tracks in this album.
Then perform the Plex Dance “light” (step 4 can be omitted) with this album/artist.
