Negative Energy Burst has a very annoying behaviour : it's a PBAoE spell (always centered on caster) yet when you have a selected target that is out of line of sight it won't cast and display a 'target is blocked' message that is completely out of purpose, since the spell is PBAoE anyway... who cares about what you have on target when casting it ?
Since it's the one self healing spell PMs use when in a hurry, this... misconception can get really really frustrating at times.