It's amazing how thoroughly they have cleaned up "offspin" bowling since a particular retirement. Used to be dodgy actions everywhere at one stage lol. Afaik they even moved away from the original biomechanics "expert" some years ago. Game is better for it IMO.
Though to be fair, I haven't seen much of Green bowling (don't watch much t 20) but from what little I have seen nothing about his action stood out. Not like some other offies over the years.