Rather than the smooth flare expected from a backlit scene, affected bodies render a distinctly shaped artefact when a strong light source sits just at or above the top edge of the frame. Nikon's remedy addresses light-shielding components inside the body and repositions the autofocus sensor.
A black dot inside the tripod socket indicates the work has already been done, which makes this one of the few faults in the archive that can be checked physically on a used body in seconds.