Return of The Mac?

I have McIntosh MX-122 surround processor and strangely the center channel drops out occasionally popping back in for a few seconds at a time, but more strangely it is only on specific occasions. On SNL the sound is perfect until the music act comes on or they show their prerecorded segment. Then and only then we have the problem and the show goes on perfectly afterward for all the talking/acting segments. One other time is The Seth Meyers show where he is opening the show and throws to a prerecorded segment. For that tape that is shown there is little or no center channel output, then the show continues without problems. When watching HBO, the promo segment before the show has no center and then when a program starts the center comes on as it should. Grammy's, same kind of problem. No Music! I could only hear the talking parts.

I've replaced all my cable boxes a few times and the unit is connected to the internet and set up for auto updates and it shows current firmware.

What could be happening here?