Graphical Bug: Witch + shield + Essence Drain = Floating shield

On my lvl 88 Blood Mage Witch, whenever I have a shield equipped, stand still and cast Essence Drain, the shield floats above my character's head. Moving while casting affixes the shield to her arm as expected.

I tested this with other shields and they all float. I tried it with a buckler and it remained on her arm. I also tested it with Fireball and the shield remained on her arm.

So, it must be something with the animation of Essence Drain. I do not know if the Sanguimancy effect from being a Blood Mage effects it or not.