Spirit boon "calm before the storm" probably not working after patch

Hi, as title says - I picked up “calm before the storm” (lucky hit: 10% chance to reduce ultimate cooldown by 2 sec) spirit boon on my tornado druid, but sadly it doesnt seem to work as intended after recent patch.
I am using cataclysm ultimate, and even when casting cataclysm, hurricane and dozen of tornadoes into pack of 30 enemies, the ultimate cooldown doesnt realy get reduced at all. I think I saw it proc like twice in 2 hours of gameplay, leading me to possible conclusion that something broke after the nerf in patch notes. Maybe the chance is 1% instead of 10%?

1 in 10 chance… twice in 120 minutes… once per 60 minutes… so it proc’d once per hour.

The thing about these “chances to proc” if it works once. In a lifetime… it’s working as intended… 10% is no different to 90% Same amount of chance. Depending on how they designed their roll system.

If you see any skill happen sometimes… it’s working as intended… because sometimes is all they can do.