1966 Jefferson Nickel. Reverse Cud? Rim Issues. Damage?

Note a Die Cud:

Note on the example on this image (dime) had a broken edge off of the obverse die, leaving an area not struck and on the reverse a void, because there was no residence (The void on the obverse die) that would form the reverse. So it is often seen as a weakness on the opposite side of the coin. Your coin was struck with extremely worn dies. (Senior die) It does even get worse as the dies are continued to be used until retirement, or a retiring die event happens..

Think die chip is what I meant. And I've never even heard of a Rim Fin.