1969 1 Cent, Opinions Of Anomaly In The Eye Of The Last 9 In The Date

I have this 1969 1 cent coin I keep forgetting that I have and not 100% sure whats going on with it. I know there is a "double date" and "double 9" but this looks like neither of the two.

If you notice in the eye of the 9 there is an incused curve, the 9 itself is of normal size compared to other 1969's and this is the only digit this anomaly is visible on.







Most Machine Doubling and Die Deterioration Doubling stays on the surface of the coin and only effects the die from wear ( Die Deterioration) or vibration ( Machine Doubling).

I've never seen it incused like this so it has me a little unsure of whats going on, I know it is incused because I can catch a tip of a tooth pick in it and I was hoping you guys might have some opinions.