[BUG] Jax immune to knockbacks/cc

At 6:47, 8:41, and other times in this match, Jax is able to completely ignore Tristana's ultimate. This is ARURF, but I'm guessing the mechanics would be the same in normal game modes. As I mentioned, this took place repeatedly throughout the match and made it physically impossible to defeat him because he could not be peeled a huge amount of the time. He would dive in, Trist would ult, and he would not be knocked away.