Hey all, I was wondering if you can tell me what type of error this coin has. It looks like a crack. If it was a scratch, The scratch should continue through the date.
Your image number 6 shows it on top of 198. It appears translucent so could be residue of an adhesive. It is too uniform in shape to be a die crack, IMO. You are showing a 1983 by the way not a 1984. You could try giving it a bath in 100% acetone. Do not use nail polish remover as there are other chemicals added to that stuff.
I question this one. If it were just damage, wouldn't the date and other devices show it? Why is the ridge, or whatever it is, UNDER the date, indicating the coin was produced after the mark was there. I lean towards plating issues before the coin made it to the dies.