I've seen this ring a few times. Read up on die strike malfunctions. Seems it could be a few things, is this even a error?
No clash. No malfunction. Worn Die Strike. This is something common on Copper Plated Zinc Cents and that's why you see it on others.
Might help a bit...a clash is when elements of the design of the obverse or reverse are transferred to the opposite side of the coin. In other words, you would see parts of the Memorial on the side with Lincolns bust or parts of the side with the bust of Lincoln transferred to the side with the Memorial.
Sorry, did not mean to post as a thumbnail. Just click on the thumbnail to enlarge. CT is going wonky on me.