~~~ and the printing process of those inlays have been explained here by someone who was in the printing business and it should be archived. Though usually found on one side, there has been at least one example illustrated here where the same die cuts from the same portion of paper stock wound up on one chip. The discoloration of the paper stock was the exact shade of your inlay prior to printing and the shades vary from lighter to darker depending from which portion of the stock they were cut. It was further explained that a quantity of them (your same chip) were not detected during production and chips were found on the tables early on.

I remember the owner of the printing business telling us (here) that the color of the white coated paper stock was in the beginning of the run and that is the reason why the different shades.