Without better pictures, I think that might be a partially filled die, could be some die deterioration. I don't think this qualifys as an error.
thanks, I will pass on spending, but I will put it in my 55 gallon drum along with all my pocket change
Let me guess... is it kind of "sheared" off at an angle? If so, and I'm not sure what the technical or accepted term for this would be, it's quite common. As for posting to the error forum, judging from past discussions on the matter, it seems many just use the "recent posts" section as opposed to individual sub-forums, so I wouldn't worry too much about it. This isn't to say that one shouldn't post to the proper sub-forum though.