Apparently though, he hasn't "passed it" to his foot/thigh but lost control onto his leg, so it is a knock on...
Personally, I think this highlights how important it is for sport in general to avoid getting too picky, the spectacle isn't reduced by allowing or disallowing that try.
But hit his leg on the way down, so it's as if he kicked it, so it is allowed to go forward.
(So say the various ex-players and "the letter of the law" in the HT analysis.)