Lee sin collateral kick bug

Happens so often on Lee Sin, whenever you use your ult and the champion you kicked is supposed to hit the other champions and knock them up the knock up doesn't register and the collateral doesn't happen the champions just walk through it like nothing happened.

Lee Sin- Kicks X Champion X Champion flies to Y and Z champions Y and Z champions walk through X Champion and doesn't get knocked up at all. Able to use spells and auto attack.