the file uploader seems to work perfect but when i try to re-order thumbnails and then update the entry the order is different.

The strange thing is that when i update again the order i made before is ok!
If i update again (with o without any change) the file uploader metabox shows a different order. Then update, and the order is ok.

this is a video of what is happening:
https://www.dropbox.com/s/ffh72yopapc5nlc/Archivo%2014-2-18%2011%2020%2021.mov?dl=0
(sorry for the sound)

this is the code of the metabox:

<?php 
/*
Title: Stills
Post Type: stills
Order: 0
*/
piklist('field', array(
  'type' => 'file',
  'field' => 'stills',
  'scope' => 'post_meta',
  'label' => __('Add Image(s)','piklist'),
  'description' => __('This is the uploader seen in the admin by default.','piklist'),
  'options' => array(
    'modal_title' => __('Add File(s)','piklist'),
    'button' => __('Add','piklist')
    )
  ));