We found a helm entitled "Underdark Mask" last night. The item gave a few skill bonuses, but also listed that it had 50 charges. There were no properties listed that would require any charges though.

Doesn't that happen when you mod an item that had charges and take off the charges.

Just happens when you give the item charges. It doesn't matter if the item has a property that uses the charges, the charges are their own property separate from functions.

"Undermask", not "Underdark Mask"!

Fixed.