Hello TvMind,
I've been around here for a while and drop in now and then but have't posted anything in quite some time. Around the time you posted this my Openbox S9, an old original started doing the Decades<>H&I channel surfing on its own. I haven't worked on a problem since I set this dish up in 2011 with the S9 so stability based on temperature didn't come to mind right off.
Mine is acting pretty odd and Movies! would do it once in a while then it pretty much cleared up. Back around 2011 there were a lot of junk capacitors that hit the market and my 2011 TV just started not wanting to turn on, so I've got some in it for certain. I was thinking I may have a capacitor problem but now I'm thinking I need to check the cables and connectors because I do get a small glitch now and then on METV which is rock solid all of the time. Maybe METV does glitch on it's own but it may be related.
I was glad to see your post and was hoping it was the signal, not the reception equipment. I did check the dish and the cables and cleaned them up a bit for good measure but they're really weren't dirty. As soon as I can I'll get out there and check everything, and the back of the box, and Vbox.
Editing the transponder from 3957 to 56, or 58 or whatever doesn't seem to help. I don't know why it cleared up but it worked for a while and then did it again, then worked, then did it again. I'm talking days apart with many temp changes too. Now it's bad and will drive you nuts glitching, but it doesn't change to H&I as much. It was changing before I could get back to the other room from doing the up/down channel to get it locked again. I have it split off to another room.
I have good ribbon cable and these seem the be the problem channels, but they just work when they want to and it doesn't appear to be temperature related. The feed is a DMX741 LNBF that's been awesome, never a problem. I didn't realize Decades and H&I were so close until I had problems, but again, it did work fine for ages so to speak. I know the feed could have problems, but it works when it wants to. I have noticed commercials don't glitch near as bad as the programming and a lot of the time not at all, that's weird. Yes, I have great commercials and as soon as the program comes back on, it stutters and may change channel.
I just wanted to explain what I've seen because it's odd indeed. I had assumed someone would say, it's just that way, we can't fix it, but that isn't the case I guess and it is working for others. Ok, I'll get back here and post what I find and I hope I didn't over look a posted fix or whatever. I do have 86S & 71Q, so it's a pretty solid signal. When it glitches it drops to 10S just wham, then back and it may be on the wrong channel. I'll let ya know.