Nocturne Shroud of Darkness not interacting with Fizz Ulti

I'm an avid nocturne player. I found this bug when I was playing normals, and have tested customs games to verify it. Nocturne's spellshield has ALWAYS been able to negate the damage of Fizz's ulti (churn the waters) - with good timing After several tests on custom games:

KNOCK UP IS NOT NEGATED BY SPELL SHIELD. DAMAGE STILL TAKEN. Basically, it's like I didn't use spellshield at all. SPELL SHIELD DOESNT BLOCK ME PICKING UP A STRAY FISH EITHER SPELL SHIELD WILL NEGATE AOE KNOCK UP/DAMAGE IF NOCTURNE IS NOT THE ONE THE FISH IS STUCK TO. (weird, eh?)

Please fix. Thanks