Rick, yes I would say the M80s are the difference. On days when the room was warm I've had the receiver go into shutdown mode several times. I did have a factory defect that I had to bring it in to repair. Apparently some of the soldering joints were defective.
It did run hot and I bought the fan before I realized the defect. Since I've had it repaired I just kept using the fan. Not sure if it was running hot just because of the M80s or because of the defects. I'll have to shut off the fan and watch/listen to something to see how hot it runs now.
