I'm with @crazyb0 on this one. It seems to me that the underlying zinc has started to leave this coin thus leaving a bit of a shell of plating. If it was grease partly filling the die, I would expect the letters to be flatter and wider than normal. Either way, its kinda interesting.
"If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz