Overpolished die. Quite common on these zinc LMCs. Not sure what you mean by muddying, mudding, or muffing.
Oh, that looks like plating blisters, which is a minor error but still only worth 1 cent since it's common on early zincolns.
I have found a few such coins, not sure what to do with them being zinc.... but have them just the same. Let us know what you find?