@support: Another example. I recently ripped the entire Robert Casadesus Complete Columbia Album Collection. At the artist page of Robert Casadesus, all 60 albums are shown in Overview:
On the Discography page, just 17 albums are shown:
These seem to be exclusively the albums I was able to really identify with the Roon database track by track. What I mean with this: The Complete Columbia Album Collection is just a stub in the TiVo database, just the album title with no tracks. The albums that I identified in this way are not shown on the Discography page. Other albums could be identified with a different CD edition in a proper manner, i. e. with track-by-track matching. These albums are shown in the Discography section.
Hope this brings a little light into the issue.