Looks like corrosion or plating blisters. Quite common on zinc cents. Not exactly sure if that is what you were referring to though.
Not an error - Environmental Damage.. Looks like some of the Zinc Cents I have dug out of the ground metal detecting over the years. Especially in ground that tends to get wet.
It's just ruined. Those bubbles are just from horseshit quality control. Not that I have anything in particular against horses.
Looks like it needed to be in one of these waterproof PCGS slabs coming soon, lol: https://www.cointalk.com/posts/2157219/.