Puzzled Over Volume Behavior

I looked at the volume controls again tonight, but for the life of me, I can't figure out what's going wrong to cause the weird behavior I'm seeing.

The volume-up and volume-down pins on the CFSound III are momentary contacts, and flipping the associated switch on the remote should momentarily ground the pin and cause the volume to change. Instead, what I'm seeing is that connecting either of the volume pins causes the volume to drift up or down, depending on which pin I hook up. This happens regardless of the buttons on the remote being pressed.

This would imply that there is a constant cycle of momentary contacts going on, which makes no sense. I can only speculate that perhaps the signal being supplied by the Keycoder is fluctuating enough in a "not-connected" state so as to fool the CFSound III into thinking it's being grounded from time to time. I don't know if something like a resistor or capacitor would help filter such noise out (if it is indeed noise). I looked at the signals with a multimeter, but I didn't see anything particularly abnormal. Very strange.

For now I'm going to put remote volume control on the back burner, and think about what else I should work on. I have a couple of things in mind.

At least I didn't fry the CFSound board this time!