What is working:
When an album is identified by Roon with a MusicBrainz release, and none of the recordings in the release have Musicbrainz work associated with them, Roon will use the track titles and composers tags to identify compositions. So if I have other tracks in my Library with the same title and composer, they will be considered as being the same composition.
What is not working:
When an album is identified by Roon with a MusicBrainz release, but 1 or more recordings in the release has a Musicbrainz work associated with it, Roon will no longer use the track title and composer name to identify composition for other tracks in the release, even if Musicbrainz has no work data for them.
So if, for example, I have a compilation album or a boxset, with many tracks, if only one track has a Musicbrainz work, all other tracks are now “orphans” even if I have the correct composer tags.