I can't tell.
You didn't take enough pictures.
Looks as if you found one..... A few more pictures may help to conclude the issue. Cheers, RickO
Anyone using the quote feature on the opening post deserves to be banned for life.
Worry is the interest you pay on a debt you may not owe.
If you're asking about the 5 in the date, I don't see anything. Of course I got confused when you showed a dozen pics of the reverse that doesn't have anything to do with your question.
Overkill on the photos.
A clear photo of each side and one closeup of the area of concern is sufficient.
That being said, your cent looks like an ordinary 1956 Lincoln.
From the other post on this coin, there appears to be a right-angle shaped bulge under the 5.
I believe that it is a random die dent from some square-corner object. But that is completely unconfirmed.
There was some question (in the other thread) if this was a clash mark.
I think that is why a number of reverse pictures were posted, so as to identify any clash marks on the reverse.
I don't see any.
To avoid confusion then, why were these pictures not put with the original thread.
Unless someone read that thread also, how are you to know that this was part of it.