It was made with zinc is the first problem.
2nd problem is it is aging.
3rd problem is, that what you see in that zinc coin, inevitably will happen to most zincs. = (
Its been in the heat and its rotting from within. As with all other Circulated coins, one may never know its true path, and our best guess is what we see.
Thats why I steer clear of all zincs. If I happen to find a DDO/
DDR / RPM, I simply offer that coin on the discounted side just to get rid of it.