2 sortable lists, when moving item to last position it becomes pre-last

Hello. This issue is repoducable only for a first time you drag item in connected sortable lists.

JSFiddle for it http://jsfiddle.net/VMvFG/1/

Actions: accorting to image[[Image(http://s3.postimg.org/hu98pfunn/sortable.png)]] do fast.

1. Grab item 4, from second list

2. Move it down, near position where item 6 can be

3. move it left to position of item 6 in first list

And You`ll see that Item 5 from first list just moves to bottom(Item 6 position), so that item You dragging becomes pre-last.

As a result it is not possible to to drag item to last position from first time, or makking some additional draging over list.