That's how containers work. If you create one of the objects then it automatically creates all of the other objects in the container.
"Parent" and "child" are kind of misleading names. A container is a group of objects. You have a group of 2 objects - a red sprite and a green sprite. When you run the layout you get 4 groups - 1 red and 1 green in each. If you want a group of 5 objects, you need to make 4 separate green objects and add them all to the container.