I didn't see it at first but you can see where "O" and "N" on the reverse are a bit diminished-- left leg of "N" and right side of "O." I believe that position is opposite the cud. Nice roll find.
That obverse die was a zombie. I'm guessing the event that caused that deep clash killed it. It just didn't know it was dead yet.
Awesome find. I have yet to find anything on a 1977 cent worth mentioning. I hope this is a discovery for you. Let us hear back at some point if it is.