The problem with the Savall Farnace album on Alia Vox may originate from the fact that his performance of the Vivaldi opera has been augmented with 8 excerpts of an opera by the same name written by another composer named Francesco Corselli. The album thus features two different compositions, and also intermixes them. Roon cannot currently correctly deal with such an intermix case.
Interestingly, this album has been reedited on the Naive label in their famous Vivaldi edition, but this time without the Corselli additions. This album is available on Tidal. If you have access to Tidal, search for “Vivaldi Farnace” in the Tidal albums, add it to your Roon library and identify it. You will see that the complete contents is now correctly picked up as one performance.
I have the original Alia Vox edition in my library, and I did experience the exact same problem as you have. In order to get the whole Vivaldi opera recognized as one performance (and not the 42 you see), you can set Work/Part tags on the 76 Vivaldi tracks (Disc 1: 7-33, Disc 2: 2-24, Disc 3: 2-19).
The 8 Corselli additions (Disc1: 1-6, Disc 2: 1, Disc 3: 1) are recognized on AllMusic as belonging to composition “Il Farnace, opera”, and this is correctly picked up by Roon as can be seen by the 1739 composition date in you screenshot. Without Work/Part tags, they are seen as 8 performances, as also shown in your screenshot. You may wonder if you could set Work/Part tags on those 8 tracks to try recover the composition as beeing a single performance. You may do so, but only for tracks Disc 1: 1-6. The important point is to NOT set a Work/Part tags on the remaining two Corselli tracks on Disc 2: 1 and Disc 3: 1. If you do so, Roon will see 3 performances of the Vivaldi opera (Disc 1: 7-33, Disc 2: 2-24, Disc 3: 2-19), which is not really acceptable. Unfortunately this will also leave you with 3 performances for the Corselli composition (Disc 1: 1-6, Disc 2: 1, Disc 3: 1).
@support This case clearly shows that Roon has trouble correctly picking up a composition performance which an artist chooses (for valid artistic and musicological reasons) to intermix with other compositions. Similar cases abound, most notably with early music performances (think for example about Monteverdi Vespers, which are rarely performed in a “pure” manner). In my humble opinion, this is a bug. Will the new Roon data model address this important issue ?