That is not finning. Finning happens when displaced metal flows between the collar and the die making a little fence along the edge of the rim.
Thanks for looking at that. The example pic from the error-ref link isn't there any more so I didn't have anything to compare it to. Any idea why it looks like that?
Glad you posted this. I have pulled 2 cents over the last month that had the finning on the edge. I didn't know what it was called and had no clue where to look!