Our Ginger has always done that. She upped her "paddling" recently when she had an ingrown claw and the Vet thought she was trying to cool it. So I suggest you carefully check that foot for sign of injury.
A taller water bowl might help. It will be hard for her to keep one front foot on the floor and paddle with the other. Of course she might very well then stand up on the edge of the bowl. And if the tall bowl does work then you have to keep it filled up to the top or she'll gag herself when she drinks.