Brakes Failed problems of the 2016 Toyota Prius

On Friday, October 21, 2016 while driving over a pothole I pressed on the brake. The car slowed but all of a sudden the brake suddenly depressed even further down and the car jerked and seemed to stall before pushing forward. I had been pressing the brake as far down as it would go and it seemed as if there would be some kind of brake failure. On October 31, 2016 while driving over another pothole, I again stepped on the brake and suddenly the pedal again depressed further down and there was a creaking and squealing sound. Then on November 4, 2016 while going over a pothole, there was a squealing and creaking sound but not a sudden additional depression of the brake pedal. All these incidents happened on salt lake blvd. Or kamehameha highway and passes under the fixed guideway for hawaii's rail system. The road is extremely bumpy and full of potholes.

Vehicle feels like it wants to go forward as soon as the gas engine turns on to charge the hybrid battery when it is stationary, is in park gear with the foot parking brake fully on and on a flat surface. When the car is running off of battery mode and the battery becomes depleted the gas engine turns on to charge the hybrid battery, you can feel the car sending power to the wheels for a slight two seconds and can also hear the brakes creaking as a result of the engine feeling engaged to the wheels even when the park gear (/button) is selected. It happens all the time and not sure why it would do that while in park. If a parking brake failure was to happen what would happen when the engine turns on to charge the battery again? will it creep forward or what? just thought this was a concern since I have not experienced this with non hybrid cars.