Shaco Q into Swain back

Hello,

I tried shaco AD on ARAM and this happened to me two times in that match, I didnt do any dmg at all to Swain´s back from stealth, game registred only Hydra active afterwards. Hit mark of basic attack is clearly visible, but not registred. This is only one situation recorded two times, I can provide second situation, but it is casted in the same way as in video provided.

Recorded 12.07.2018 (today), version 8.13, public client