When I put the rear seats down flat and drive the vehicle I randomly hear what sounds like the rear seat release mechanism firing. It happens most often when there is some weight on top of the folded rear seats. has anyone else experienced this? It sounds exactly like the sound one hears when pressing the buttons in the tailgate to release and fold down the rear seats. I'm about to take the car for a routine service interval and wondered if this is a known problem or something unusual.