Significant FPS drop whilst glowing (having the glow effect) and looking at yourself in third person (front/back)

For some reason, viewing yourself from third person back/front whilst glowing (glow effect) causes a significant FPS drop.

F3 menu + toggle third person perspective (front/back, any work) - it should be immediately noticeable.
Additionally, this affects other players around the glowing player while looking at them.