I have a page with html5 coding which creates a video player with closed captions enabled. This works perfectly well in all non-IE browsers, and while IE actually displays the on/off toggle switch with the correct label gleaned from the html5 coding, it doesn't display the captions. If I hit a page with (almost) identical coding directly from IE, captions work just fine. IE Developer Tools doesn't reveal any problem in the console, no cross domain issues, etc. It just doesn't display the captions. I'm stumped.
Working page (not via Moodle):
Broken (in IE) Moodle page: