Bubbling of the zinc under the THIN copper plating is VERY common. While I can not say with certainty, bases solely on the image provided, that your 1984 cent is a victim of this, the likelihood is EXTREMELY high.
I still suggest that you learn all you can about the coin making process. Doing so will make it easier to understand anomalies you may find.
What do you mean we're out of coffee??!! Off to the espresso stand!!