Zac Bug (V. 8.4)

I recently played a game with a zac on the enemy team and when he cast his e (Elastic Slingshot), he was able to cast other skills during the animation of his e. For example, he's able to q (Stretching Strikes) me while he was still midair of his e. Here is the download link to the replay if anyone is interested, just spectate the zac. http://www.mediafire.com/file/qwb5ng84ub9fh1w/NA1-2727583262.rofl I also found a link on youtube showing this recently found bug. https://www.youtube.com/watch?v=NT8ELo-Q2QM