The contact owns a 2021 Chevrolet Malibu. The contact stated while the vehicle was parked, the ‘Shift to Park’ message was intermittently displayed on the instrument panel and the vehicle intermittently failed to completely shut off or lock. No warning lights were illuminated. The vehicle was taken to a dealer to be diagnosed; however, the vehicle was not yet diagnosed. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 21,000.