Looks like the die was getting worked over with heavy die polishing. Note how the column and field is loosing its normal design.
On a die chip, the die is loosing material and the die is falling away, making a raised area on the coins struck as the die crumbles away.

On a die chip, the die is loosing material and the die is falling away, making a raised area on the coins struck as the die crumbles away.
























