I hear them go “bang!” after I put them in the oven and then they’re bent diagonally 😂 I suppose it could be because of the temperature difference there, too. 

 🤣 😅 

So it seems uneven heat distribution is also a thing. 

https://www.americastestkitchen.com/cooksillustrated/articles/6782-how-to-fix-a-warped-baking-sheet