The Crit Hax, Parahax, Flinch Hax, and pretty much everything else on PO is very Glitchy and unstable, which is why some " Less Skilled " Battlers pretty much use nothing but moves like that on PO.
It isn't quite as stable as the actual games in Crit Rates and Such, and added effects tend to happen more than usual,
But if it were perfect and exactly like Pokemon, what would be the sense of using the Games for and Competitive battling?
So It's just how PO is, you kinda have to get used to it, I've gotten 4 Crits in a row on a opponent ( Not from this site ) Using PO before, thats just how it is.