NON-pivot foot. You can rotate on your non-pivot foot as long as you don't hop or drag. And I am not sure where you are seeing a drag? The only relevance of a foot drag would be the pivot foot (which I don't see) or the non-pivot foot AFTER the pivot foot is lifted (which I don't see, either).
Where is the drag that you think (might) make this a travel?
Also, he never changed his pivot foot. I think that might be confusing the conversation. You cannot change your pivot foot without a dribble, shot that hits the rim, or a pass. But he doesn't do that here.