KENNEN ULT INVISIBLE

I was playing a ranked game today when i came a cross a kennen with the blood moon skin. At level 6 i immediatly noticed the invisble kennen ult after i died from the death recap. I dont know how this happened but every time he ulted the rest of the game no one could see it except the lighting bolt when it hit someone. I dont have any proof but i hope you will please look into this.