We ran close to 500 shots, with a 60% chance of vamp aura, and hex having a 50% chance of blocking, it should be a 30% chance of hitting with vamp aura. We had 5 or 6 29+ streams of shots not proc at all. The odds of this happening 1 time is
.3 ^ 29 = 0.00000000000000068630377364883
or 0.000000000000068630377364883%. Considering this happened multiple times it is a fairly good sign of something wonky going on. I know non quantum CPUs don't really have randomization, but that is still pretty low odds, and the fact we did it multiple times means it likely wasn't a false positive.
My math skills for probabilities is a little rough, haven't used the math in years, but I'm pretty sure I got it right XD