It can't be an error as that couldn't happen during the striking of the coin. Hard to say exactly how it happened unless you were there at the time but somehow a one cent coin was pressed into the surface either by accident or on purpose. Interested in what others have to say.

I have been collecting large cents for a very long time and I have never seen this before. As you can see I have examined this coin at very high magnification. I cannot find any marking that would indicate hammering another coin into it. I cannot find any marks that indicate pressing. I also think that if this is transfer corrosion the wreath from the reverse would also be visible even if faint. I find it curious that the highest point from the reverse imprinted on the highest point of the obverse without any other part of the reverse showing ? Thank you for your input. I look forward to others opinion as I am at a loss for an explanation.

Typo correction version, sorry

8 hours ago, Ray, USMC said:

 I also think that if this is transfer corrosion the wreath from the reverse would also be visible even if faint.

It is visible.