Got this error today. I'm thinking it is a firmware / software issue, though, as both repeater cameras are blank when I activate them or shift to reverse. Also noticed that my Sentry videos show garbled pictures for the front camera. Was able to get a mobile service appointment for this coming Thursday.
Bad thing is....my car turned 3 years old this past Thursday.........go figure.
Add to that, my 3 year old phone (bought the same day as my Tesla) decided to stop working this morning. Woke up to a blank screen, and nothing I do will get it going again. Quick Internet search shows a lot of folks are having this issue with my model of phone (Google Pixel 3XL). When it rains, it pours.....
Keith