Yes, for some reason you can usually use the channel down button to get a picture on the next channel down (going up never works). If you then go up a channel to get back to the channel which was blank, the picture has usually returned.
Often you have to do this to get several channels working as you keep pressing channel down, then it goes back to working normally again.
Could be a programming bug in the software, but it’s been there since I got my box a few years back, so I suspect it could be a tuner issue.