Kled Passive Firing Early

So I haven't played Kled but I have played against him enough to understand his passive can be very misleading. I try and kill Kled in two steps. The first, knock him off Skarl. I then wait for CD's to come up again and re-engage to kill him. Often times I die being one hit away from killing Kled because his passive bar lies to me. It shows his bar at roughly 50% he auto's once and it goes to roughly 65% and then on his next attack hes back on Skarl. Can someone explain this to me. Is there a ping delay where on his screen his bar reaches full? What % of his bar does an auto on a champion generate? What % of his bar does one of his rifle shots on a champion generate?

Thanks,

#KledIsBusted