Jinx's AS drecreased by ~35% vs frozen heart
I was fighting a leona up close when I noticed my AS droping from the max 2.50 to 1.70, at first I thought I was exhausted but then saw summoner spells and she had flash and ignite, oh and no Randuin's Omen, nobody in the opposite had exhaust. I think the frozen heart disables the Q attack speed stacks plus reduces the 15%.