What has been seen cannot be unseen. Noticed this today doing some Lightroom work. Taken with my iPhone and zoomed in a bit - it's smaller in real life yes. Seems to be stuck on white and is notable on dark colours and shades. Annoying. If it was not dead centre I would probably leave it because the rest of the macbook is perfect. Had my iPad mini replaced for the same problem. Still within the first week window.