So this issue has came up again today. I'm at a redlight with my foot on the brake, I started to feel the pedal "sinking" into the floor. The car starts rolling forward , I released the brake and applied again. Brought it to the dealership, the tech tried to replicate the problem, but it worked normal again after I dropped the car off. This is the 3rd time that has happen. He said "its normal due to the car having brake assist." I don't find that normal at all, more of a safety concern!