Hi, I also had that bug. I installed Stretch from scratch yesterday and noticed screen flashes (or screen refreshs, I can't really say) sometimes when I was typing on the keyboard. Once, I got a black screen quickly followed by a system shutdown, I couldn't find much in the logs (with my knowledge).
Someone pointed me to this bug, I did the workaround (cp xserver-xorg-video-intel's xorg.conf into /etx/X11), and the bug disappeared. No more flashes. I hope the shutdown thing won't happen :) Thanks, gagz
