Hey guys does this 1987 have a very weak strike. Im still a rookie at this. But if I had to guess. That would be my answere. Now chime on in experts. School is now in session.
From my experience it looks more like natural errosion. IMHO Environmental damage.. I have found similiar looking quarters near river beds tumbling around in water and pebbles.
It's not an error. Notice all of the small hits and dings on the coin and rim. It's been tumbled and eroded. Maybe a rock tumbler, maybe a burnisher, maybe some variation of a dryer coin. Regardless what caused it, that coin didn't leave the mint like that.