[BUG, THIS IS NOT LAG] Champions Locked in a Running Animation then Glitching to Another Spot

I was playing a few days ago against a Jax and while he was running away from us, i saw something weird. It looked like he was sprinting in place at his turret so we jumped on him and started killing him, but right before he died, he warped in the middle of all of us and we were stunned. He still died, we were confused but attributed it to lag. Then yesterday, we were against a Warwick who was doing the same thing, he was running in place so we started attacking him but right before he died, he glitched over and was ulting me. The weird thing is I took damage as if he had been ulting me the whole time and the damage I had dealt to him and seemingly the damage from skillshots went away. This time though even the enemy team saw what was happening, their Fizz said something like "that hacks" or something.

I have absolutely no clue on how to repeat this, so if anyone has seen this and can get footage, or has any idea on how to repeat this please post your own thread or comment below.

The only thing that these two things have in common is they have targeted gap closers and the glitch apparently appeared to happen right as they used it.