So I've been watching all the posts over the weeks hoping that GM would figure something out, it didn't seem like anyone had found a solution. Fortunately, i was able to figure it out. I did a few things to fix it but i'm not entirely sure exactly which one did it. I knew it was coming from the spoiler, so i dropped the headliner down. You may be able to drop just the rear section of the headliner down, but to do it right and without the possibility of putting a kink in your headliner, and to give you more room its better to drop the whole thing down. Once i did that i removed the spoiler. There's about 10 bolts holding it on along with 2 yellow clips. I'm almost positive that it was coming from the clips themselves so i removed them entirely. The spoiler is completely secure without them so there's really no need to worry about them not being there. The second thing i did was put electrical take between the surface of the spoiler and the truck itself where all of the bolts go in. I thought the noise could have been caused by the spoiler moving and binding up against the roof of the truck. So i figured adding more padding between them would help. When putting it back together i made sure the bolts were all really tight to make sure it wasn't going to bind up. I also covered the two locations where the clips were. Its been 2 weeks since i did these steps and it hasn't made a popping noise since. It would happen 3-4 times every time i drove it. Again, i'm almost positive it was the clips causing it but i wanted to be sure. Hopefully this helps anyone wondering what its from or how exactly to fix it.