Trying to determine what caused this error. Is it a die chip that just happened to land here or what ?
It is either a small die chip or a plating blister. Poke it with a toothpick and see if it deflates. Keep up the hunt!
Wait, the filled 8 or the blister under the 3? If it's the 8 then its a die chip; very common for 1983 in that location for some reason. I usually find at least one per box. If its the thing under the 3 then I agree with the previous posts.