Fixed.
Bit of a mess to clean up; the Sleet Shaft was using copypasta code from the Psi Noise Generator so it's possible that looting the staff would block the ability to later loot the Noise Gen. Had to hackjob something together to potentially account for that - it won't be perfect, but it's as good as I can get it given the potentially lossy information available to account for it, but the Sleet Shaft should no longer be multiply-lootable.