Dark Armor: Dark Embrace has an effect where your entire character pulses to your FX color. There are multiple that have it, I think it's also associated with the minimal FX option for most powers.
I find it incredibly nauseating, I assume that's why they made a version of the fx that (isn't supposed to?) have it. That customization option appears to be broken though, it's only slightly slowing it rather than eliminating it. I think it's slowing it rather than entirely stopping it. (or maybe I've removed some of the sources of the blinking, it's blinking at least less)