Got this in the mail today! So happy to have this release. The music is gorgeous. I do wish we'd have gotten a pressed CD of Vol. 1 to go with it, but I'll take what I can get.
LLL and Bear McCreary know, but if they were going to discuss it publicly they probably would have done so already.
My guess is that Mattel decided to release Vol. 1 on CD themselves, and decided the CD-R route would be the most cost effective. That probably didn't perform as well as they'd hoped (in part because people like us don't love CD-Rs), so they passed on doing the follow-up volume... allowing Bear McCreary to release it himself on his own Sparks & Shadows label, which LLL distributed.
It clearly makes little business sense for McCreary to re-release a physical edition of Vol. 1, so I think we are probably stuck with this incongruity.