[GAMEPLAY] Spell shield not blocking Riven's Broken Wings

Was just in a game against Riven as Sivir, and when she would go in and i couldn't shield the stun in time, i would always try and block a q with my spell shield to try and take less damage. But, her q went straight through my spell shield and didn't block the damage at all. I did not test it with the third q because the shield doesn't last long enough.

1. Play Sivir against Riven.
2. Have Riven use Broken Wings.
3. Attempt to block with spell shield.