Well as long as I have to return one of my CMs I figured it wouldn't hurt to experiment with trying to eliminate the channel jumping problem. The one I have to return has issues with breaking up signal and also the channel skip problem.
First I removed the cover of the unit and next the front of the unit. That part was a little tricky since one needs to hold basically 3 tabs at near the same time while sliding one side, then the next away from the front. Reassembly was easy.
Going off 2 tips I've read here at AVS, one in this thread and another in a thread specifically talking about this problem, I tried both, one on the channel up and one on the channel down.
Note I don't know how a person could really do either easily without first removing both the unit cover and also the front of the unit.
First I noted that neither button skipped channels when I pushed directly on the little micro switches with the front of the unit off, that was good. Next on the channel up I used TooLittleTimeZZZs tip of using a piece of black tape between the button and plunger piece that's attached to the front panel button. To keep the tape from falling off later I stuck it to the top of the switch and draped it over the front of the switch. The switch itself was only a couple mm dia. so I didn't think just sticking it to that would hold up for long.
Next I went of a tip from 3elementsmissing but instead of using spray lube I used a small dab of axle grease on the little plunger.
I put the front cover back on the unit and WALA, neither button now skips
So take your pick, axle grease or a small piece of tape, or don't use the front panel buttons all options work. Thanks to the above posters for the tips.
P.S. I'll be posting this in both this and the other thread since this topic seems to be active in both.
BTW I also had NOT removed the plastic film on the front of the unit, but in my case anyway removing it did not help the channel skip problem.