A couple possibilities come to mind.
1-
PSD Damage that occurred after the coin was in circulation.
Post Strike Damage, any defect in a coin acquired after the coin was struck at the mint.
2-
Struck Through Grease at the mint. Grease got trapped in the die, then the coin was struck.
Either way, a photo is required to determine either.
Or the guy that made the die couldn't spell.

Dan