[GAMEPLAY] Lee Sin Ultimate Ability not Knocking enemies up

Several times, while playing Lee Sin, I have tried to go for one of those crazy Reddit plays by kicking an enemy into the team to knock everyone up and damage them. Although, sometimes the champion getting knocked back goes through other opponents and they do not get knocked up, or damage. This happens to me at least once every game, and seems to happen at random but it seems pretty common to me. (this is not my video but is pretty much what happens to me) Rito pls