I agree with you COOP. could be not the same flow or the border of the flow which it is not offen see. This could happened some rare times. Till now I have only 4 to 5 coins like this. The tests was positive on real coins. When I received and pass in laboratory, was this end of wrong mixture of ally, but internal has delamination. why ? because we deal with two different materials: one is rhomboid and the other is cubic. To made a deeper test cost, and I have no idea if it is worth. Before to do those tests is better to have the weight, the thickness also.
In previous post I say that many do woody fake jobs on coins for money. Not new not old. A surface microscopic analysis will say.