Show the edge please. Could be and end of sheet incomplete planchet. Clipped is the incorrect description even though it is used. Blakesley effect seen opposite the area in question. IMHO (Or altered)
Kind of looks filed to me, but I have faith in what @paddyman98 says. Perhaps @Fred Weinberg might comment.
I think it is a genuine Incomplete Planchet. The way the edge tapers at the "clip" and the bit of Blakesley Effect. Your coin has a lot of wear which makes it a little more difficult to discern. http://www.error-ref.com/_curved_clips_/