Consuming Questions seems to be bugged?

Exploring Chayula in depth and am finding that Consuming Questions is not really generating much for ES. The idea is to get a decent shield pool that J can keep regenerated with attacks and not have to use Grim Feast.

I currently leech 40% on 170-380 physical damage per attack (Ice Strike really cuts down the Phys). Mana stays full at all times but ES only restores about 20 points per hit.

Anyone toyed with this and have similar input?