I had this happen on my Surface 4 Pro, on the left side of the screen. Not too long after I saw the stripe, the left side of the screen buckled out away from the backing (so it no longer folds absolutely flat. The surface still works ok. But now I see the yellow stripe on the right of the screen and wonder, if it is a glue defect, if that side will buckle out as well. Up until now, I thought this was an issue of overheating. My Surface is long past it's warranty, unfortunately.