This one I encountered in a mint roll I purchased from the bank. Thought it was interesting. Anyone know the reasons for this?
If your question is about the rough surfaces that look like bumps, its most likely a plating issues and/or bubbles
That's my third error coin I have found in recent years. I've also found both a quarter dipped in copper and a dime partially missing its plating.
Your coin is not considered an "error" as much as it is just something which happens when copper is plated over zinc. This condition is quite common.
As said above, plating blisters/bubbles. Here's a link for more info: http://www.error-ref.com/?s=Plating+blisters