Contour Mini Box

Had major problems last week which resulted from Contour 1 box having multiple faulty tuners. Thanks, Stephanie, for the diagnosis. Had a tech come out and replace both boxes as well as installing a filter on the lines running into our condo unit. Everything was working fine; until today. On the mini box: Have a specific channel (22) designated as "power on" channel. Tried switching from that to another (47): channel was blank, then automatically switched BACK to the power on channel. I was able to go to another channel (20) fine. Went to switch to a completely different channel (8) : it went blank than BACK to my previous channel (20). Some channels worked, some did not. Unplugged/replugged box and all is well: for now. Any idea why this may have happened? Some channels were affected which others were not. But why would it do this in the first place? Hopefully, not another bad mini!