Darkness Enthroned bug?

I have Darkness Enthroned with gloves bonuses. When I applied "Courtesan Mannan's Rune of Cruelty" and "Fenumus' Rune of Draining" on the belt it is now saying "You cannot use this item. Its stats will be ignored".

Both runes are gloves runes so what gives?

Oh damn. Well that's makes sense as I have one already on my gloves.

Some kind of tooltip for the exact reason would ease up life on this. As one who does not check all of the patch notes I would probably had not found this on my own.

Well thanks anyway for pointing out this!