The contact owns a 2021 Kia Sorento. The contact stated while at a red light, the vehicle stalled. The contact turned off and restarted the vehicle and the vehicle returned to normal operation. No warning lights were illuminated. The vehicle was taken to a dealer and was diagnosed, and it was determined that the battery needed to be replaced. The vehicle was repaired; however, the failure persisted. The vehicle was taken back to the dealer to be diagnosed; however, the cause of the failure was not yet determined. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 43,000.