A particular cloak suited for Paladins, the description states "8 charges" but there seems to be no ability that can actually make use of those charges.
Also true for the Goblin Bonesaw, I think the Hunting Knife too, and a bunch of other items.
Not a bug... just left-overs from the evolutionary history of these items. (i.e. when you make 50+ unique drops per quest, you tend to use copy/paste a template and work from that...).