This question may be superseded by the new way to drive Sonos from B2.
I ripped a box set of 4 CDs. No data for any of them, so they became 607, 608, 609, 610 on B2. I renamed all 4, with artist and album name, the first track and a track midway through for each album. This all looks fine on the B2 WUI. If I have to type in the data, I leave the original number at the end of the album name, because I have had issues before, and it shows me which album data has been entered manually.
A scheduled update added them to the Sonos lists. The albums on Sonos retain the labels 607, 608, 609, with the tracks named 'track 1' etc. On the other hand, 610 has its full title and track names.
The only thing I can think of that might be different, is that the compression to FLAC may, or may not, have happened before or after the Sonos identified them in the NAS.
This was done on the previous software, B2 Oct 23 2020, but similar problems have existed for a while. I have several CDs that just have a number of the Sonos, instead of the album title. About 25 to 30 % of my collection has had manual data entry, but this is the best example I have of the titles being different.
This seems to be different to the 'tagging' issues, which I am aware of, as it means the Sonos listings are more than not quite the same as the B2.
Cheers, Alan