Syndra Flash + (Dark Sphere + Scatter Weak) = Stun combo visually hit but enemy kept moving

I recently played a game where I was playing Syndra Mid against an Ahri Mid. I flashed towards Ahri laid out a Dark Sphere with Q and did the E Scatter the weak to stun Ahri. She started running away after my flash but even though it was in clear range and I saw it hit her (there was a graphic color showing that she got stunned and that the ball hit her clearly), she was able to keep running without hesitation. I told my friend what happened and he was spectating my ranked game and I told him about it. He waited until it happened and he witnessed the same thing, confirming that it was a bug and that it should have hit and stunned her. This affects Syndra's already nerfed Stun Q E combo with recent issues, but there are still bugs like what I encountered. Please fix so Syndra can even try to compete equally with other champs. Appreciate your help, keep up the awesome work :)