The sacrificial embrace gloves’ buff cannot be consumed except by a channeling spell. The text does not say that so I presume it is a bug.
attached is a screenshot where I have just directly cast an elemental spell (static is on cooldown) but you can see the buffs are still showing with 10 stacks
I would love to build around this item but need it to be fixed first! spellblade dosen’t like to channel spells 
thanks!