I have noticed that the HTML5 video/audio player (AppleCoreMedia) on mobile Safari on iOS 7 excludes all cookies, even first-party cookies. Not even sessions cookies are inc
I had the similar issue with Safari. I was using  tag inside the html loaded by jquery. Safari did not include cookies in the request for the audio source, therefore it did not load properly. But somehow it worked after I refreshed the page with CTRL+F5 - it sent cookies with this total reload...
I solved it by adding crossorigin="use-credentials"... Nasty problem.