Using a draggable with a connected sortable causes error if sort returns false

Using a draggable with a connected sortable causes an "Uncaught TypeError: Cannot read property '0' of null" when sortable.sort returns false.

I guess that the sortable destroys the dragged element and draggable wants to access it afterwards.

Example

$(".sortable").sortable({
  sort: function(e, t) {
    return false;
  }
});
$(".draggable").draggable({
  connectToSortable: ".sortable",
});

Codepen

https://codepen.io/anon/pen/XZELqm

Current workaround

• Return true in sort and handle cancellation in stop callback.
• Use $(t.item).trigger('mouseup'); in draggable.drag to stop drag.

Background

I want to implement cancelling of a drag operation into a sortable. Sort returning false cancels the operation on mousemove instead of waiting for mouseup and stop.