I know there's more than a few posts on this but none of them fully addressed my issue. The back window on my 3, which has 826 miles on it cracked last weekend. It's the inner laminate layer is what cracked and the outside and inside of the window are perfectly smooth. It appears the defroster arced to the vertical line, which I can only guess is the FM antenna or something similar and caused the plastic inside to brown and melt. It is a manufacturing defect. People seem to think this is because of tint but how does that make any sense? I've had every car I've ever owned tinted and I've never had a window melt and break. Tint is a thin plastic and ceramic layer of film on one side of the glass. It does not change the thermal transfer properties of the actual window itself. I get a new window on Monday (under factory warranty as a manufacturing defect) but Tesla will not cover the $320 it will cost to get my tint reapplied. Anyone had any luck getting Tesla to cover the tint? If you want to get your back window tinted, I'd recommend running the defroster a lot beforehand to make sure your window doesn't break.