Although I have a B2, and have used Mac, Windows, and Linux computers, I confess I have no idea what you mean by "connected a new/old Macbook to my B2". Nor do I recognize the term "CDDB Rip".
To the best of my knowledge, a B2 will not download anything automatically from a computer that happens to be on the same network. Nor should a Mac. Perhaps you have turned on DLNA on the B2, and are running some software on the Mac that is scanning the music folder on the B2 and building an index of what it thinks you want as a music library?
If you could explain exactly what you did, maybe this would make more sense.