Yep, the pinhole effect is likely from an imperfection on the surface of the light layer that sit on top of the eInk screen. Whether it is a bubble due to faulty manufacturing, or a scratch, or whatever, it creates a very tiny, but bright pinhole of light on the screen. Some PWs had one or more of them, many, perhaps most, did not. But there were some PWs that had several pinholes. They do not effect the operation of the PW, but they might bother the user as s/he reads due to the distraction of a tiny bright spot on a page.