Using your demo I find two bugs:
-when you add a new file you can’t remove it, can remove it only after save the post, in the previous version that was working perfect.
-the second is worst, if you has more that one upload field and if you use any of them to upload (work ok) but if you use any other to upload a file the file will apear in the first upload field used.
Again that happened using a demo in the plugin, Any idea?