I was at the dealership yesterday because I'm hearing a lot of squealing coming from the back brakes as well as a metallic scratching sound.
He said the backs are worn and the sensor is probably touching the rotors. I could get them replaced right now but as it still shows 900 on the rear brakes, I am waiting in an attempt to get the rotors below the threshold and replaced before my free maint ends.
The SA did say that the rear brakes do wear quicker than the front ones. Something about how it applies them to prevent oversteer.