On the lower serif there are some examples of this happening that the punch was damaged and created this look:
http://coppercoins.com/lincoln/dies...ie_state=mdsNote the information box above the images.
Quote:
1952D-1MM-012
| D/D/D TILTED & TILTED (MDS)
CONECA: RPM-012 | Crawford:UNKNOWN
Wexler: WRPM-012 | FS#:UNLISTED
coin photographed is credited to Bob Piazza.
A nice split serif can be seen on the upper mintmark.
The bottom serif shows evidence of a damaged punch.
I'm not saying this is a coin from that die, just that there was a damaged punch that year that made this happen.