This seems to be a relatively recent bug I have noticed.
Unless you were already blocking, it seems now it is impossible to block soul blast. I see the start of the animation, and with code's combat alerts - both of which worked just fine before the Reach patch - at that point it is how too late - your character seems stunned and unable to do any action at all, which makes this ability impossible to block or roll/dodge.
This is super annoying if for no other reason that it does a huge amount of damage. Has anyone else noticed this?