@Raanan_Yechezkel, this is an extremely common problem. There are several solutions.
Raise the issue and wait for roon to fix it with their meta-data suppliers. With streamed content this may be the only solution as roon provides very few editing features for streamed content.
There is a very simple work-around that will not work in every case, but does in this case (also works for local content as in your case). “Un-identify” the album and then roon will correctly group the compositions. The minus is that now roon will have very little metadata which you will then have to manually put back in. In this case, composer, artist, album art, release date, a few other things. I have this album on Qobuz and that is what I ended up doing as roon provides very little meta-data for this particular album anyway. In other cases where roon provides much more meta-data you may not want to do this and put up with the incorrect composition grouping instead. So it “depends”.
If you have a local rip, then you can manually tag the composition hierarchy using WORK, SECTION and PART tags using an external 3rd party tagger which roon will recognise. You do not have to do this for all the compositions which with a box-set like this would be a lot of work. You can just do it for the affected Op. 12 sonata. There are a lot of threads here on this topic going back years. Do a search, also look at the Knowledge Base. Solutions depend on whether you are using windows or mac.
In my experience, you should first adjust the [work] and [movement] in your favourite tag editor, then in the album’s modify/metadata preferences, you should check the’files’ button in ‘grouping compositions in multiple parts’ (last option in first section). A rescan of the album might be necessary for changes to appear.
I had the same issue on several albums and fixed it easily with this procedure.
Thanks for the detailed reply. I use iTunes for meta data editing and the track is correctly defined. I’ll tell Roon to use the file meta data for these tracks.