Brake Master Cylinder problems of the 2021 BMW X5

The contact owns a 2021 BMW X5. The contact stated while reversing out of their driveway and making a right turn, the display screen on the center console went red. The contact depressed the brake pedal and the pedal went all the way to the floor. The contact took their foot off the brake pedal and depress on the accelerator pedal, when the contact noticed the display screen showed the vehicle went from hybrid mode to sports mode on it's own. The driver had to press the hybrid button to get the vehicle back to normal. However, the next day the contact was driving at an undisclosed speed and approaching a red light when they depressed the brake pedal the vehicle jerked to a stop. The contact then depressed the accelerator pedal but the vehicle would not move. The contact waited a few moments and depressed the accelerator pedal again this time the vehicle was slowly moving forward. The contact was able to pull over to the side of the road. The vehicle was towed to a local dealer who inspected the vehicle but was not able to duplicate the failure. However, they stated that the failure was related to the brake system and replaced the master cylinder. Although, the vehicle was repaired the contact was concerned that the dealer could not provide the reason the failure occurred on the vehicle. The manufacturer was made aware of the failure. The failure mileage was 9,700.