Yellow-legged Mud-dauber Wasp

Mystery in clear focus now.
Yellow-legged mud-dauber builds mud nest. It stocks nest with hump-backed orbweaver spiders and lays it's eggs on them. Blue mud-dauber opens nest, removes hump-backed spiders and stocks nest with unknown spiders. Lays its eggs on them and reseals the nest. In this spotting we see the yellow-legged mud-dauber putting it's final layer of mud over the nest. Apparently not aware the Blue mud-dauber had taken over the nest. See link for detailed information on Yellow-legged mud-dauber.