I feel like even if i build 100% around debuffing somebody's fire rate, if they built enough fire rate it seems to ignore the debuff. maybe a bug with super high amounts of fire rate?
Nevermind on this. I checked the replay and thought mystic slow specifically wasnt working, But the few times i thought i hit them with spirit damage I missed. And Slowing Hex's fire rate slow was functioning normally. chalk it up to the crazyness of late game fights being visually chaotic so hard to confirm when you land hits on the right person