Found this rolling cents from a coin counter bag. Something going on. Strike Through? Lamination? Lots of die chips? It is not glue, solder, or any foreign material on the coin.
I was thinking the same thing...until I saw the IGWT close up. That part looks like a planchet flaw to me.
What possibly could have occurred at the Mint to cause this? What makes you so sure that it is not glue? Those "open bubbles" sure do look like glue or some other foreign matter was placed on the coin. Have you tried to remove it with acetone?
I let it soak for 2 hours earlier today in acetone. Then I tried rubbing it off with a soft rubberish dental toothpick/flosser. A little dirt was removed, but nothing else came off.