Fiora's Lunge (Q) sound will be overlapped by Yasuo's Steel Tempest (Q) if Yasuo is in the game.
I left a post here about 7 months ago stating that Fiora's Q will not make her usual sound if a Yasuo is present in the game (Yasuo's Steel Tempest sound will be replaced). This is highly reproducible (possibly even 100%), and all you need is a Yasuo and a Fiora in the game. The two do not have to be on the same team in order to have this effect.
This is in the Patch 6.8 notes.
Please fix.