The ghosts of the Dragon cultists in Forelhost use normal armor and weapons which can be looted from them after death. Since they're spectral appearances only, it makes no sense for them to drop mundane armors and weapons.
Dragon Cultist ghosts in Forelhost drop no loot except their ghostly ectoplasm. (Use unplayable gear for them)
You cannot recover arrows from their archers by getting hit. (Perhaps use unplayable ammo with the no ammo weight keyword?)
Check out other ghosts for the same kind of weird drop behavior. Nightingale Sentinals and Valdar have been reported to also drop blood and/or loot.