I just found this 1953 P in a roll and it has a string of copper that runs from the U in Trust over to the top of Lincoln's ear and it resembles a piece of string that has been wound too tight and knotted up.
I can tell nothing from the photos but what you describe sounds like a die crack. Can you take a photo with less magnification so we can see more of the "die crack"?
1953 error This is neither a die crack or gas bubble. You can see where this string of copper actually drapes over top of the rest of the coin and begins where it is actually connected to the bottom of the U in Trust. As you can see in the second picture, this string of copper drapes over Lincoln's hair.