I've run into a problem that has got me stumped: after upgrading to WP 3.6 my sortable metabox fields are not saving their position when you re-order them. Below is my code:
Metabox Setup: http://pastebin.com/9NMXwDt3 (the function that saves the metabox data starts on line 582)
What I have is a metabox that contains a repeatable box, inside the repeatable box is an image upload button and caption text input. Everything works fine, I am able to add more repeatables and sort them, but when I save the post the repeatables go back to their original position.
If anyone would like I can give you login details to see the live version.
Any help would be greatly appreciated.