I see it. It depends if the outline is obtuse or incuse to which of the following is the cause. 1) If a Mint Workers does too much grinding and polishing of the Die along the edge of Lincoln's bust which created a beveled edge around the bust and which produces a raised outline around his' bust on a struck coin. 2) If the grinding and polishing is done down inside the incuse details (in this case, Lincoln's bust) moving from the center to the edge, it will cause a flare along the edge of the details and this shows as a sunken outline around the details on a struck coin.
Frank