So I was thinking how could several hundred MacBooks get the same problem... I'm sure someone has already thrown this out there but I'll do it too. Has anyone thought if the affected MBPs are ones with dGPUs or... rather if just before having the "stain" the MBPs ran hot. The keyboard and the vents are right below the screen and could possibly cause it to happen. Like say your watching a video or playing a game or whatever, and then you shut off the computer then close the MacBook. There is still quite a bit of heat that accumulated that didn't have time to cool down and maybe that is what has been the biggest cause of the problem. Or am I crazy? lol Kal.