Sounds like a filled die error.
It happens when grease or other build up fills the devices on the die, then those filled devices don't get transferred to the coins minted with it.
Pictures would help confirm this.
EDIT: I see you posted a picture, thank you.
The picture is too blurry to see the details.
Edited by cwb
01/14/2018 01:46 am
01/14/2018 01:46 am


























