Me too. I asked about this here (there's a video): https://superuser.com/questions/1277194/screen-glitching-when-mousepad-is-tapped-or-keyboard-is-pressed
Happens in linux-image-4.9.0-4-amd64 and linux-image-4.9.0-5-amd64, haven't happened so far in linux-image-4.9.0-3-amd64.
