The astronaut's visor is gold, thus tinting any reflection. The sun is centered behind the photographer, not directly overhead. Thus from the astronaut Schmitt's point of view, he should be seeing the shaded side of Cernan with shadow falling away behind Cernan. The hot spot on Schmitt's visor is consistent with the illumination angle as evidenced by Earth's terminator.
Looks like another failure in spatial reasoning. It's likely this specific claim has never been made before, but the same broken assumptions and handwaving claims can be made about nearly all the 7,000 lunar surface photographs. He's not a genius for applying the same faulty reasoning to a new photo.