draggable connected to sortable - error when the items are dragged back to a droppable

Say we've:

1. Some draggables

2. one sortable

3. one draggable

If we drag one draggable(1) and drop it into the sortable(2), and drag it again to a droppable, then the following error occurs:

event.target.hasAttribute is not a function

if(!noPropagation) this.element.trigge...n, [e, this.ui(inst)], this.options[n]);