Mana Drain/Lightning DoT Bubble Issue

I've run into two mobs with the 'Drains Mana and Deals Lightning Damage over time' affix that are not centered in their bubble, making it near impossible to not die to them.

In both instances they were in the 'ring' so whenever they'd turn to face you, you were in the bubble, so even melee distance wasn't an option. Also, in both instances these mobs were also exhibiting usain bolt levels of speed, so I assume they were hasted as well which might be related?

You can see an example in the following picture:



Additionally, the small blue 'ring' around the NPC doesn't feel representative of the actual size of this aura. There are faint lightning wisps much further out that I believe actually represent the size of the bubble, but they are much harder to see making it very difficult to understand a 'safe' engagement distance.