I have been really interested in this coin. I figure someone of knowledge would coin in!! @paddyman98 @physics-fan3.14 (I know there’s more members) Do you have a quess??
I never realized that coinstar was such a popular place, it makes sense that the automated equipment would reject foriegn or error coins. I remember the fuss about vendors that had to change their equipment to accept the changing coins and currencies and the expenses associated with it. Great Find!!
It is definitely not reeding, and almost certainly didn't occur at the mint. I suspect the damage on the edges probably occurred in some sort of vice grip or pliers.