I am in Las Vegas and I am having exactly the same problem for several months now.
While scrolling the TV Guide with the PG/CH Up and Down buttons on the right hand side of the remote, the TV suddenly freezes up. When I turn off the TV and turn it on again the Cox restart screen appears with a series of colored squares and eventually the guide re-appears but everything on the right half of the guide says "program unavailable" and about 3 minutes later the entire guide becomes visible again only to act up unexpectedly without warning.
I have two TVs and both have shown the same problem and switching remotes between them has not helped.
A few days ago we had a TV/Internet maintenance-related outage for several hours and after that the problem seemed to have gone away but it proved to be just wishful thinking on my part.
I have not bothered to call Cox support because from the past experience (and I have been a Cox customer for more than 20 years) I know how incompetent they are and most likely to send me on a frustrating wild goose chase so I have resigned myself to living with it.