Jeffersons Eyelashes

While looking thru some rolls of nickles I noticed something odd. On many of the 2001-Ps, and a few of some other dates the portrait of Jefferson has eyelashes. Don't believe? Take a look at these photos of 4 different nickels. A 1973-D, 1980-P, 1997-D, and 2001-P.









I found a handfull after only a few minutes, so they must be pretty common. Here are a couple mint set nickels with the regular(NO EYELASHES) obverse.





The same anamoly on coins that span 8 years(so far), and two different mint provides a clue to how this happens. Because the marks are nearly identicle it must be something in the minting process. Any ideas? I've reached the end of my ideas.Perhaps I've discovered a new variety or a new type of error.