Itasca electrical issue

It sounds like the backup camera could be a real clue. For the smart people, I assume it probably is always on but no picture displayed until the shifter is put in reverse. If so that would indicate the issue is somewhere around the steering column. If you can get it to do it again, try moving the gear shift slightly or if you can stop and just move the gear shift a little and then from drive to park and back. You mention you stop and restart the rv and it often goes away, which would require putting it in park to start. That tells me that is the first place I would look. If you had a wiring diagram you could isolate how the gauge arms and B/U camera are connected. Their common point is possibly your problem. I bet they share a common ground.