I am also unable to retain changes made to playlist reordering. I reload the page and the order reverts right back to how it was before.
Also, when saving a track with an apostrophe in the title, the plug-in adds a forward slash before it (i.e. “Devil’s” becomes “Devil\’s”). Please resolve asap.
I am having the same issue. Single site install of 3.5, no plug-in conflicts, no console errors. Behaving identically across a variety of themes and browsers. Definitely not an isolated issue.