"Zincolns" pennies after 1982 are notorious for rotting. Especially in the soil they deteriorate due to their poor composition. I've heard of them deteriorating in plastic proof sets due to the humidity.
I downloaded your images and noticed one interesting thing.
Where is most of liberty ?
If zinc rot, where are the holes ?
I don't see any smashes right there except on about where the B would be.
Damage aside, I find it interesting. But I am strange lol
Can you please take a clearer, closer pic of Liberty. I can't tell.