The contact owns a 2021 GMC Yukon. The contact stated that while driving at various speeds, the Forward Collision Avoidance system erroneously activated, causing the vehicle to suddenly slow down. The vehicle was taken to the local dealer who serviced the Forward Collision Avoidance system camera and sensors. No further information was available. Additionally, while driving at highway speeds, there was a knocking sound coming from the engine compartment, and the seat restraint failure message was displayed. The cause of the failure was not yet determined. The manufacturer was notified of the failure. The failure mileage was 20,000.