Chance orbs not working on normal items with "advanced" tag

Take some white "Advanced Shoes". No prefixes or suffixes.

Chance orb says to use on a normal item but used on these shoes you get a message saying "the rarity of this item cannot be changed".

However, if you use the orb that changes a normal item to a magic item, it works fine. So clearly the rarity of this item CAN be changed.