Prius brake failure

Anyone know why my 2010 Prius has 3 times now failed to stop when brakes were applied on a steep downhill in slight rain? Happened a year apart with no slick road and with tires both new and old. I pull up to a stop sign on a grade, apply brakes, the car slows, then there are metallic noises and the car glides 3-4 feet before stopping. I’m lucky no car or person was in front of me. Honestly not a skid at all. Service tells me I don’t know about anti-lock brakes but I’ve driven with them on cars for many years with nothing like this. Need some advice before I kill someone.

You do know the Prius has two modes to the brakes, right? When you first touch the brake pedal, you activate regenerative braking that uses the electric motors as generators to recharge the battery pack, and the drag slows the car. Press the brakes further, and the hydraulic brakes activate, using the brake pads and rotors to stop the car. You’re having a problem with the module that controls that regenerative braking mode. Is the factory warranty still in place? You need a specialist to look at this.

Metallic sounds bad. Have your pads been checked?