Have you gotten out of the car to look at the rear camera to see why the car is asking you to check it? Or are you assuming all is well because you can see an image on the display?
Could the camera be at an incorrect angle, or perhaps the camera is getting wet because the rubber boot (#13 in diagram below) that protects it is damaged. You can’t see that damage if you remain in the car or the Roundel closes and you can’t see it when you do get out of the car. Or is the Roundel remaining open after the camera turns off…or is getting stuck as it tries to open/close?