Probably will not be covered under warranty. Two ways to fix it though are ride the brakes, not excessively, but get them HOT. This will fix it if they are glazed, but not heat glazed. If your pads are walking back and forth on your calipers you can tear them down and spray some disc brake quiet compound on the back of the pads. That is about the only two sources for noises at your mileage. The other would be wear indicators but you should not be having that problem.