That is strange! Did the diameter wear down also? Gotta be up there on the list of "strangest finds in a penny roll". I found a shield nick in a nic bag last month. Congrats!
With all the weird things happening when sorting, I will believe everything. I found a new nickel in a penny roll some time ago. It broke the thing in half and was hanging the roll together by a thread when I got it from the bank, it was a accident waiting to happen.
I tried putting the nickel back in a roll tube with some pennies. It went back in ok, stretching the paper roll out some where it was. Redbook lists the diameter of the shield nickel at 20.5 mm, current nickels are 21.2. That difference might explain why it goes in the roll ok. I don't think the diameter has been reduced, there is some rim in places. This nickel is extremely worn and pitted I'm thinking of trying to raise a date with buffalo nickel date restorer. I bought some restorer several years ago but haven't used it. Any tips on restorer would be appreciated.