Brake Loud Noise problems of the 2015 Toyota Prius

Issue started after 2 years, when wet and cold as I back up and put my foot on the brake pedal, a very loud noise heard coming from the back? it lasts as long as I put my foot on the pedal. Expressed my concerns at peterson Toyota dealer locally, but the technician stated that "it's normal", could be the brake hydraulic booster system? the issues still continue as of today. I do record the noise when it happens.

I purchased the vehicle new in 2025 and I have been experiencing brake failure issues every time I attempted to brake over either a pothole, a slick surface like a metal sheet at road construction or wet roads the brake would fail. All the red warning signs would come on in the dashboard and the brakes would make that loud horrible noise. I love my Prius, I don't want to get rid of it. I was hoping Toyota motors would have a fixed for the braking system by now as this is very unsafe specially inexperienced drivers. My goal is to pass this car to my teenage daughter when she goes to college in 2021, but this may not be possible if Toyota doesn't to up with a solution to the problem.