Chance for recharge slow proc: Aggro?

So, I cleverly put a chance for recharge slow proc in my smoke grenade.

Which now aggroes enemies.

Whoops.

Am I right to blame the proc?

Yeah, debuffs will generate agro.

I figured, since the power was a to-hit debuff that didn't generate aggro, other debuffs would be covered by the no-aggro thing.

Apparently, in fact, that particular /dev blaster is now on hold until I19.

Another example of this would be the Achilles' Heel %Chance for -Resistance when socketed in Analyze Weakness. The skill is a single target -defense/-resistance that doesn't generate agro, but when socketed with the Achilles' Heel proc it has a 20% chance for additional -resistance and generates agro when the proc fires.

Is it only if the proc actually fires, or is it active even if the proc doesn't? I ask because on groups of 2-3 opponents, I consistently drew aggro by smoke grenading them, and it should be only on the rough order of 48% likely that at least one was hit. (Not 60%, as you might calculate, because that overcounts cases where two guys were hit.)