Projectiles Ignore the Cursor if the Caster is hit by Quinn's E.
Quinn's E forces any projectile being launched to go in the opposite direction from the caster's command.
The ability says nothing of this effect, so it must be a bug stemming from the addition of flipping opponents around.
Casseiopia's ultimate recently had the similar bug where her ultimate would change direction in regard to flash fixed, so this is clearly not an intended effect.