I had a chance to fear on my helm as well. It's actually extremely annoying and I ended up gambling for a new one. Since you stack area damage and concentrate enemies inside the bubble, you don't really want them to run away.
It's not particularly harmful, but it does slow you down when they separate from the pack, and it is quite annoying. I was surprised how often I noticed it being irritating in rifts before changing helm.
But as Astrayon said above me, take the helm if its an upgrade, just don't roll something INTO a chance to fear, as it's not beneficial to you as DMO.