The contact owns a 2024 Mercedes-Benz GLE450. The contact stated while driving 70 MPH with the cruise control activated, the vehicle suddenly decelerated to 15 MPH. The contact became aware that the cruise control system had changed the set speed independently. The vehicle returned to normal functionality, but the failure became a regular occurrence, with the vehicle accelerating or decelerating independently. No warning lights were illuminated. The vehicle was taken to the dealer, who was unable to diagnose the failure. The contact was advised that the cruise control should not be activated. The vehicle was not repaired. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA Hotline for assistance. The failure mileage was 1,500.