Strange Oscillation

Alright, I need to get to the bottom this. On a couple of CD's at certain passages, the music goes into an oscillation and won't quit until the volume is reduced or the disc stopped entirely. My playback source is an Ayre C-5xeMP, Plinius Tautoro pre and Plinius SA-103 amp. Interestingly this only happens on a few CD's and usually when there is a sustained chord such as from a keyboard note that is held or a sustained vocal. Two examples are Pink Floyd, Dark Side of the Moon, track one about mid point with the EMI Japan release CDP746001 Z. I also have the MFSL issue and it plays with no problem. Another example is Patricia Barber, Cafe Blue standard redbook release during a sustained high pitch vocal note and only at high volume. So what causes this to occur? It is obviously related to the CD itself since DSOTM MFSL issue plays just fine. Can anyone enlighten me?