I just uploaded a new album with Beethoven’s Piano Concertos. One concerto (no 3) is not properly recognised and listed as separate tracks instead of a single concerto. I double checked the metadata (all tagged by me) and all tracks share the same album, artist, composer etc metadata. I don’t remember ever seeing this before and have no idea how to solve or more importantly, what causes it.
Are the track titles in your tags exactly as shown in your screenshot?
I think Roon is processing your tags to display work/part layout for the other concertos, and is failing for this particular concerto. I’d suggest double-checking that your track title tagging is following the same schema as the other concertos.
If you do want track titles exactly as you’ve tagged, I think turning off work/part layout for this album (or globally) should do this.
Roon is ‘seeing’ this as a three disk set in my case - I guess you have a download, so there is scope there for differences in behaviour.
I love them and have numerous different versions of the same concertos. I am a bit pressed for time at the moment so it might be a week or so before I can check the titles again, but I did check before and found nothing unusual. However, you never know.
Roon only “explicitly” uses your local title tags in all scenarios with single part works. Even so, there are relatively frequent posts where roon has not applied that general rule consistently.
With multi-part works roon does not in general respect your naming convention unless you “unidentify” the album. Instead it seeks to match your homegrown naming convention to the canonical form supplied by Rovi/allmusic. That is why Op. 19 and Op. 58 in your screenshot looks nothing like your homegrown convention for Op37.
This problem of failed grouping for multi-part works is extremely common in roon so if you have not seen it before then you have been very fortunate. In fact roon introduced parsing for WORK/PART tags years ago precisely to provide a manual override when its auto-grouping fails.
The surest way of solving your problem is just to edit the WORK/PART tags of the rogue composition to comply with the Rovi/allmusic canonical form as has already been suggested. You don’t seem to want to do that so you can also try unidentifying the album to see if you get the result you want. Sometimes a more minor edit will also work. For example changing Op37 to Op.37 or changing your delimiter from “-” to “:” so that your homegrown convention complies a little more closely to the canonical form and roon can make a match. But there are no guarantees so mostly editing the WORK/PART tags is the quickest solution.