I've a necklace that disables the helm slot. When wearing this necklace, I am unable to equip a moon-on-a-stick, which is not a helm.
I can provide more information/screenshots if needed, just message me on IRC.
You might need to rephrase this bug.
You did not name the necklace or the character. You did not mention the type of helm you attempted to equip, or if it had this effect with multiple helms. You should mention whether other amulets are working for the character right now, just to rule out it being a bug with the character. Also you didn't explain how the moon-on-a-stick staff has anything to do with the helm or the necklace, is this an additional bug? If so which item, the helm or the necklace is causing it. Basically, provide the details needed to debug the item.
I'm assuming the item is "Necklace of the Innate." Are you able to wield other weapons, or is it just the moon-on-a-stick item that presents a problem? Is the helmet slot correctly unavailable?
You are correct on that, Howland. The helm slot is correctly disabled, and it seems to be only the moon-on-a-stick that does not work.