Hmm, my first thought would have been running low on free memory but from the tray you arent running lots of programs and your signature says 16GB RAM. So can't be that. Is it with all RAW files? or just a couple in particular? if it is just a couple, maybe they are corrupted coming off the card and when you reset they are going back to a smart preview or something? Some raw formats contain a thumbnail in the "sidecar" so you may be seeing a low res preview when it looks ok, then seeing the knackered actual raw when zooming in. No errors on the filesystem?
Can you close photos, and open the file straight out of finder using apple camera raw? Is it s supported raw format? I mean it isnt a new camera and you havent updated the camera raw software or anything?
Are you getting any screen render issues anywhere else on your machine?
Also that model uses a Intel 3000 graphics card right? 384-512Mb VRAM. Maybe as you are running dual displays, it is running out of free VRAM??? does it do it if you go to just the laptop display?