Qotra's Regulator bug?

I tried using the Qotra's Regulator shield, and discovered that the "lose x% of life when you deal a critical strike" applies to *each* enemy you crit, even if you do all those hits in a single instant cast (e.g. with Frostblink).

I think this might be a bug.

If it's not a bug, please consider changing the way the item works, because, as it stands, the only purpose it has it to kill you.