Thanks for the call, I am always hesitant to call a CUD as I have incorrectly described one in the past, this would be my first; it is hanging by a thread.
Is that area solidly attached to the coin, or is there a gap below the piece. Looks like a retained lamination (hasn't peeled off yet) to me. If solidly attached, with no space underneath, I agree with Chris. Sure looks like you could peel it off though. You can see the shadow underneath.
It could be either, but it would be a lot easier to know for sure with the coin in hand. To be honest, I don't like the term "retained cud" because it doesn't make sense. If a cud is a break along the rim that extends into the field, then how could it be a retained cud if it hasn't separated. That's why I sometimes question the "so-called" experts from some of these websites. Chris
I would say a "Retained lamination". A cud does not have design elements on them as they are caused by a missing part of the die. http://www.error-ref.com/cuds http://www.error-ref.com/retained-lamination/
With a "retained CUD" the field and rim has separated. It is only "retained", or attached, at a hinge point within the die shaft. This is why there has to be a horizontal or vertical shift noticeable on the coin. I do get your point though Chris. The term itself is contradictory. It's an oxymoron like "deafening silence". I think it is used to simply differentiate between the anomaly we are discussing, and a standard rim to rim arching die crack, that hasn't split vertically down into the die shaft yet.
To my mind this is a lamination error. In general cuds are blobs that fill the holes left in a fractured die. Laminations are roughly the same level as the rest of the coin and the damaged part looks like the rest of the coin. What the "experts" and dealers say is likely to be something entirely different. Regardless this is a great find.