Brake Fluid Leak problems of the 2016 Volkswagen Golf

Brake failure. The car was being driven around 20mph, when a �brake: fluid low see owner's manual� message came on. After seeing this message pressure was applied to the brake pedal and the pedal went to the floor. The pedal made a �chattering noise� as it moved through the pedal stroke. The parking brake was used to stop the car. This was easily recreated in a parking lot and at the local dealer. The warning light came on each time the car was started after the initial incident, and when pressure was applied to the pedal, the pedal easily went to the floor making the same chattering noise. There were no symptoms before this incident. The brake system seemed to function as it should and had every other time the car was driven. I checked for brake fluid leaks at the master cylinder and at each of the four calipers, and did not find any leaked fluid. It appeared that there was still brake fluid in the brake fluid reservoir. Upon initial contact, the dealer said they had never seen this before. After their initial assessment by the dealer, they believed it was a master cylinder issue and the seal on the side of the brake booster had failed, and brake fluid leaked into the booster.