1798 Draped Bust Cent With Partial Extra Thick Planchet

Thank you for welcome and the input! I knew PMD was a possibility, but I couldn't figure out what would have caused it. Definitely didn't think of someone trying to saw through it from that direction! Think the top edge of the lump was maybe the edge of where a vice was squeezing it?

Edit: Part of the reason I initially questioned PMD was that even the bottom of the obverse and other edges make it look like it's 2 layers fused together. And the area where it would have been sawed is still so smooth. Not saying you're incorrect! Just trying to envision exactly how it sheared like that.