It looks like there is metal flow into the area so in my opinion it looks like there might have been something in the die.
No, it is definitely a groove of sorts. I'm just unsure of how to tell the difference between a genuine struck through and post mint gouging. The fact that this coin is circulated and has considerable wear probably doesn't help! Michael
In that case I would guess it is a lamination error. But as you know - I've been wrong on errors more than once
