Brake Light problems of the 2008 Chevrolet Silverado

If I am going down the road and press my brake pedal and then let up a little bit so that I don't have as much pressure on the brakes the brake lights go out. They go out before I am off of my brakes. So if I am coasting down a hill and apply my brakes and then realize that I have applied too much pressure and I have to let out a little bit to calibrate the pressure correctly my brake lights do not stay on, they go out before the pedal is completely released. I want my brake lights to stay on until I let off my brakes completely, it shouldn't matter how much pressure I have on my brakes, if my brakes are on so should my lights. The reason I am concerned with this is because I had someone nearly run into the back of my car. Also if I am sitting at a redlight and ease up on the brake pedal but still at a full stop, the brake lights go out while I am sitting there, I have to press my brake pedal all the way down to get the brake lights to come on and stay one, if I have any pressure on the pedal the lights should stay on. This has scared me plenty of times at night because I will be stopped and the person behind me has to slam on their brakes to keep from hitting me. I believe this is a design flaw in the brake system with my 08 Silverado. I have been to the dealer to get this fixed as a warranty issue but they say "failure to replicate problem. " so that is why I am filling out the complaint.