Slightly Concave Lincoln Cent

I ran across this Lincoln Cent today. The obverse is very slightly concave and the reverse is slightly convex. The highest point on the obverses is lower part of the roof on the memorial. It's just a hair higher than the rim. Considering the details of the coin are in tact, it seems likely that this is something that occurred during the manufacturing process but I don't know. Does anyone know how something like this comes about?

The concavity is difficult to see in the picture and subtle even when handled. In the image, the concavity can be seen best just slightly in from the rim. There is a change in color as the as the surface of the coin changes slope. The cent is also slightly thicker on the right side though the variation in thickness isn't all that out of normal range.

Anyone know how this happens?