I'm a bit puzzled by the Draggable update function https://greensock.com/docs/v3/Plugins/Draggable/update(). It doesn't seem to do anything, even in Blake's demo https://codepen.io/osublake/pen/JBwxjr
Commenting out this.update() still works.
In my added Codepen I change the position of a draggable in 3 different ways, and either update is not needed, or it doesn't help.