I suspect that you are seeing the UV luminescence of the white plastic just below the surface of the base plastic of the chip. Not being familiar with the true color of the Maxamillion chip you have, but lets just say it is black. I suspect that the thickness of the black layer at that location is thinner and/or the white (UV reactive) is thicker than normal.

A similar condition exists on clay composition chips where an overly large inlay covers over a part of the inserts and if those inserts are UV reactive, you can see still see that reactivity through the inlay. For that Maxamillion Bud Jones, which uses injection molded processes, I'll bet that at that location there is a build-up of excess plastic from being the injection point. Since an additional layer (black) will go over that, the tolerance for the white layer does not need to be precises and is probably thicker. So much thicker that the black is thinner right there and the UV light penetrates a bit into the black and reaches the white below.

But that's just a guess!

Jim