Enchant a silver weapon like silver sword, silver greatsword etc.
When selecting your enchanted silver weapon it will only show "especially effective against undead" but not any other enchantments on the weapon.
It does glow and price of weapon are increased and the enchanter table shows.. or rather doesnt show the silver weapon you enchanted meaning its active on the weapon.

This results in a lot of confusion if you just made 14 different enchanted silver swords.
(Silver sword + bannish enchantment = epic profit)

Means a "bug" in either weapon description or menu.
So... Another one for the fixlist.