I have a jQueryUI sortable list. I need to keep track of each new index of the element while dragged, based on the "change" event. But it only works reliably from slow, up to normal drags. If the user drags the element quickly, the "change" event loses track of some indexes with no error thrown in the browser's console. 

Here is a jsFiddle that shows the problem:https://jsfiddle.net/yhp3m6L8/2/

In this jsFiddle, you can drag an element and see its index change. Below the list, there's a console emulation keeping track of the indexes in black. 

If dragged quickly, some indexes become red. This is the problem as this means their previous position is overlooked by the sortable script during the change event. The continuity is broken and this continuity is primordial for my needs. 

I tried to  paste the code here but the system won't allow me to post because it considers the message as being too long. So you will find the code in the jsfiddle. 

Thank you for your help.