My first guess would be either a dirty, or hard-to-read CD would be the culprit. I know the 10-disc changers were never very good at reading CD-R discs and much preferred commercially "pressed" media.
A "misfeed" (ie: the changer doesn't load the disc properly) could be at fault here too, I suppose. If you were to hit a bump at the wrong time or something, I suppose.