The contact owns a 2023 Porsche Taycan. The contact stated that while driving approximately 5 MPH in stop-and-go traffic a second vehicle crashed into the rear of the vehicle causing the vehicle to crash into the rear of a third vehicle. The contact stated that during the incident the braking system had malfunctioned and the vehicle did not immediately stop while pressing the brake pedal causing the rear end collision. No injuries were reported. A police report was taken at the scene. The cause of the failure was not yet determined. The manufacturer and local dealer were not contacted. The failure mileage was 3,000.