Ornn E Knockup unstoppable or a bug?

I just, like legit right now had a fight as a sivir adc vs an enemy Ornn, and no matter what, when i used my E spellshield to deflect his knockup, the spellshield got consumed, my mana was refunded, yet i was still CCd, and yes i confirmed he hit the terrain first and not bumped into me first to consume the shield then hit terrain.

Did i just got fucked because of a Little silly bug or is Ornn E legit inevitable upon impact?

Edit: If anyone would be nice enough to tell me how to record and publish my last Plays i would very gladly post visual proof of this occurance