Side/rear Glass problems of the 2012 Kia Motor Sportage

I was waiting at a stop light when I heard a huge pop sound almost like a firecracker and when I turned around to see what it was my entire back window was completely shattered. There was no rock or any object like that to be found anywhere so I have no idea what caused it, maybe pressure or an air bubble? it seemed like a default in the window to me but of course it's not covered under warranty.

Driving at approx. 35 mph, exiting the 405 s freeway in socal on the brookhurst n exit ramp, heard a loud pop. Checking the front windshield, I see a long 13 inch crack in the glass at the top right hand corner, beginning at the edge of the windshield where it's connected to the car body frame and extending left toward the center of the windshield. After parking the car, I inspect the crack, which is completely smooth, indicating that it was not possible for a rock to have chipped or gouged the glass to start the crack. Any glass dust was found at the edge of the windshield where the crack originated. Clearly, a stress crack. This is a safety issue because if the front windshield were to crack or shatter unexpectedly during normal and safe operation of a moving vehicle, then that would certainly be a possible cause for an accident and/or injury to the driver and any passengers.