I can describe one repeatable issue that might be a clue.
I was recently re-ripping about 2500 CDs, and I was using dBpoweramp for ripping because of the metadata support. However, I also had JRiver open at the same time because I was listening to music. So whenever I'd put a new CD in, both JRiver and dBPoweramp would detect it, and JRiver would spawn a dialog box with metadata in it. Usually, I'd dismiss the JRiver dialog box, and go on my way.
However, if I failed to dismiss the JRiver metadata dialog box I would see strange behavior: when the cd ejected, the dialog box would go away on its own, but when I put in the next CD, JRiver would show the metadata for the previous CD. In fact, no matter what CD I put in the rest of the day (until my next reboot), JRiver would only display the metadata for that one old CD when I put a new CD in.
It sounds like folks in this thread are seeing that same kind of "sticking" behavior.
The best way I know to reproduce it is to
1) put in a CD, let it get detected and pop up the metadata box,
2) wait a few minutes, then eject the CD (using a hardware button) without dismissing the box
3) put in a new CD
The new CD will show the old metadata. For me that's 100% reproducible on a couple of computers. It sounds like that isn't the only thing that can cause this, but hopefully it will help in troubleshooting.