Brake Light Problem

Hey guys I need some help understanding the brake lights on my wifes G6, we were told about a month ago that the lights were coming on when I was driving (foot off brake) and going out when I was stopping (foot on brake). when we got home I tried the brakes and had my wife look and they were working normal so I let it go, today I followed a Malibu that was doing the same thing. I remember the lights worked off a switch on the pedal, did GM change the way the brake lights operate? What would cause the lights to work opposite to normal?

Stp

I think on the newer GM cars the brake, and turn, circuit runs through the hazard switch. How does this affect the rest of the lights at night? I am far from an expert but I would start with the hazard switch.