Hello. I can’t find anything similar online so I’m not sure if this would be a lamination error or just something else that happened to it while in circulation?
Hmm, that it sort of looks like one of my coins after I removed some significant verdigris from it. It left a grainy pock mark like that behind - but my approach also stripped all the toning from it. More experienced members will have the answer, I'm sure. Thanks for sharing and welcome to CT!