Looks like part of the copper plating pealed off. Probably due to environmental damage or plating bubbles.
It's hard to tell on your picture. It's a bit grainy. If the material is missing, it could be a detached lamination.
I'm inclined toward "splashed with something corrosive", but it's a bit hard to tell from a photo of a screen showing a photo of a coin... Welcome to CoinTalk!
Ok.. Copper plated zinc cents started in 1982 It's not any kind of error.. Just corrosion of some sort.
Second photo does make it look more like a Struck Through. The ghosting of the 19 remind me of a unretained lamination. More photos with light at different angles may help with a correct answer.