Is this a bug or intended? I can not use Drain Essence on mobs I knock down/stun with Invasion until after they stand up again.
The tool tip doesn't say you can't use it against stunned/knocked down mobs, it only says you can't use it on mobs that are recently drained or fed upon.
Please update the tool tip or fix the bug.
"Now I stand, the lion before the lambs and they do not fear. They can not fear." --Arthas Menethil (aka, The Lich King)