My vote is for this being a die clash as well. We see this location pretty frequently with wheat cents, but that seems to be part of the letter N in CENT. You could look at an overlay to see exactly what detail from the reverse corresponds to this under Abe's chin.
"If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz