TJG,
Assume for a moment that you, like I, do not know what you have run into. Then read your post and see if there is enough there for one to have the barest clue what this is about. "Change" is not enough for me to go on.

I find that I, as a reader and contributor here, would find your topic mildly interesting if I dealt with the particular components you mention, but without a description of the actual probem, I would not lift a finger to search the hundreds of possible remote control button pushes for the problem that you DO NOT bother to describe. I would either ignore the thread or at least wait for someone to say, "give us an example."

So, give us an example. Does some obscure button on the MC-12 remote (shift TV-M, for instance) make some weird change on the Runco, such as turning off the no-signal-present auto-power-off? Or does changing the MC-12input turn off the Runco? See how the particulars can make a difference in the interest level, or even in our ability to recognize if we have seen what you are referring to? In particular, if you do not give us any examples, we can honestly tell you that we have never seen any problem, and maybe we have never tried the combinations you are having problems with. You will be sitting there wondering why nobody else has this problem, when maybe we do.

Please give us examples.