:hfive:
Until they change the rules, they'll happen all the time. I'd say close to 80% of jump putts are illegal. They either have both feet in the air when they release for a traditional one (like you saw), or in the step putt one their front foot comes down, or again both feet are in the air.
¯\_(ツ)_/¯
I dont know about 80%...I'd give a player the benefit of the doubt, but really would hope a player would control his stance better. When you get 6" off the ground when you release the disc, like in that vid, that's a bit much! :\