A character with an attached Vulnerable trait only took 2 damage when successfully using a Jarring Block to negate another attack, I would expect the trait to kick in and increase it to 3 damage. James Gandalfini blasts a cone of arcane energy! James Gandalfini moved. Krelvin tries to block the attack - and succeeds! Krelvin took 2 Crushing damage. Krelvin discarded Jarring Block. Melvin passed.
I think there's an issue with Jarring Block in general - it's damage doesn't scale or get soaked by armor. Has been an issue for quite a while.