1990D missing clad layers?

[UtahSilverMan]

Our coin sorter at work rejected this cent. When I looked at it, it is missing any hint of copper. It is also slightly concave on the back - and of course convex on the front. I’m not sure if that is post mint or not.

Is there a way to tell if this is an actual missing clad layers error or a coin that has had the copper removed? I saw in one forum that lines across the obverse is one sign of a missing clad being authentic, and this coin has that. It also has some great detail on the reverse. The first two photos have pretty accurate color.