Not an error. Post Mint Damage Somone probably took a knife to it But wait for a more advanced expert to take a look
Wow! That coin is as old as I am but in much worse shape than me and I have 6 implants in 2 toes, a total knee replacement and a patch in my gut. I have more metal in me than a car bumper. My heart goes out to that coin. It's had a very rough life. All PMD.
what was it about the rim that makes you think it was done that way at the US Mint ? PMD -is any damage that happens. Just think of all the places change can accumulate get run over etc over time; get dropped in machinery, etc.