On my Priceless Staff of Ribeth, it has gone to appearing all gray, and the red ball in the head is gray.
It was fine up until sometime in the last year or so, seems like it got broken around the time the Demonskin staff and other demon weapons got the textures upgraded. That may or may not be connected to the issue. I mention the Demonskin staff because for years, it simply borrowed the look of the Ribeth staves. Perhaps the old/original settings/textures got left out or discarded once the Demonskin staff was changed?
It should have the three twined twigs making up the staff, black, with a red ball in the center of the staff head. The other regal staves are likely also affected: Exceptional Staff of Ribeth, Word Staff of Ribeth, and a third that I can't think of the name off the top of my head (Deteriorated maybe).