Any ideas why "Surface Cut" failed to remove all of the material in this situation?
I don't get any geometry errors or other indication that the feature failed. Pity I 3D printed parts without running an interference check on the STLs (the assembly comes up clean w.r.t. interference from this cut failure), but such is life. Nothing a razor won't fix. Good thing this isn't P20.
The cutting surface is fully knitted and extends beyond the target body in all directions, but the cutting surface does return a "unable to thicken the surface" error if I attempt to thicken it by a small amount, so I suppose something is rotten in the state of Denmark.