Is this a known issue and is it being fixed? I notice it all the time, finally thought to get some screenshots. Minor spoilers, as I took these in the first part of the new patch (simulation). To be clear, this is not just an issue I am seeing with these enemies, but have noticed it for quite some time.
http://i.imgur.com/M8L96zY.jpg
http://i.imgur.com/oTKUiIj.jpg
I left the combat log in there so you can see that the damage is from the ground target and not an enemy (and all enemies are dead in this screenshot).
I stood in place and just capped a bunch of screens so I could actually capture the damage numbers.
In the first one, I am standing close to the circle, but outside of it. You can even see that the negative effect is shooting out at an angle to hit me.
In the second, I am pretty far outside of the circle and still getting hit by the AOE.