Hi Jim,
One possibility is....
Sonos needs to have the metadata tags populated for artist , album title, and track name in order to index your Sonos library.
The B2 does not, as it uses the physical folder and file names to build its index
I suspect that for some reason these tags have not been populated when you ripped these latest CDs.
Was the B2 connected to your network and the internet when you ripped them ?
If you initiate playback of one of these "missing" tracks using the B2 Web UI and playback to your Sonos system does it work ?
What does the Sonos app interface show once playing ?
The way round it is to add these tags using tagging software on a computer or re-rip on a computer with software that adds the tags and then upload the
ripped files to your B2.
You would need NAS enabled on the B2 and appropriate software on your computer.
John