Read the kit and you'll find out
He triggers those effects when he activates his Corruption. Corruption activates either on his sp3 or, what is almost certainly happening to you, ten seconds after his sp1. After he throws his sp1, you’ll see a timer on your status bar. When it expires, he activates his corruption, reversing your controls and briefly going unstoppable and unblockable. If you are throwing a special when Corruption would activate, it will not activate. This is how you play around it without a direct counter. You should also try to push Knull to his sp2 and learn to dex that to avoid Corruption activating at all.