* This is not a bug. It is an aspect of normal PCB fabrication and is nothing to worry about. What you can see is the light reflecting off the edges of the apertures in the insulating solder mask coating over the surface of the PCB: ![enter image description here][1] There are tolerances on the alignment of each separate element of the construction of a PCB: the drill holes, copper pads, solder mask and silkscreen. In your photo you can see a small misalignment of the pads around drill holes (the pads are not exactly concentric with the holes: you can see this more clearly on the via). You can also see what appears to be a small misalignment of the solder mask with respect to the copper of the pads and the copper flood. In fact the solder mask is almost exactly concentric with the hole and it is the misalignment of the copper that makes the solder mask appear offset. * You will however notice that although, in some places, the edge of the solder mask is close to the edges of the copper plane, it is always inside the gap between the copper flood and the pads. Therefore the copper is always fully covered. You will also notice that the solder mask does not encroach on to (i.e. cover) the edges of any of the pads (the via is fully covered). If the copper were uncovered anywhere, you would see the characteristic colour of bare copper. [1]: /editor/20180127/5a6c8eb82392e.png

Thanks Andy. Interesting read. I will do a little cross checking of this information. That said, why do one not see these edges on PCB's that does not have a copper flood?