Or in other words, I have found evidence of another die crack. This time on a 1916 Penny.

On this particular coin the evidence of the crack can be seen across the top of DEF, starting to the right of the D and finishing to the right of the F.

On closer inspection the crack is a little larger than that, starting on the D before DEF.
I searched through a load of Google results relating to American Pennies/Cents and I found this thread relating to die cracking on the 1916 Penny. This thread could also give me a bit more info on the recessed ear issue that I am also having.
At least this is another oddity for the collection.