So I've had my MBP for a while, and I just noticed this today. I was watching a movie on my external display in full screen, and it blacked out the internal display. However, I had the brightness at full, and I noticed the pattern on the screen. It's only noticeable at the top 2-3 brightest settings and only when the screen has very dark content. I was also in a fully dark room. Anyone else see this?