2016 P Roosevelt Dime -Incused Area On Reverse?

In the 4th pic down there is a struck through spot beside the base of the torch. This spot showes a highlight on the side away from your light sourse and a shadow on the side nearest your light source. This is what I would expect to see if the anomaly in question was incuse.
What this area does show is two equally dark lines near and away from your light source. My thought is the anomaly is a stain where the drying of some liquid left a dark residue on it's outside edges.