[GAMEPLAY] Yasuo Steel Tempest fails to deal damage on certain occasions

While laning vs Riven, I noticed whenever use cast Q right before being knocked-up or stunned my Q would fail to deal damage.

1. Select Yasuo, use Q on enemy champion. (Note: More noticeable with less Attack Speed.
2. Have enemy champion with hard cc (Leona or Riven) hit him as he casts.
3. Yasuo deals no damage.