It doesn't look like a CUD but I don't know what causes this effect on the rim. Just looking for an explanation!!!!
That is rim finning. It folded over in circulation. Rim Finning a sharp edge of metal that found a weak spot in between the collar and die chamber during the strike.
This type if question reminds me of the kind CoinTalk member Insider would ask.. But we would have to wait until tomorrow to answer