SCORM module loading, very large delay on IE11 with Windows 7

Issue: When clicking on an uploaded SCORM module, the window starts loading but shows a blank screen. Browser icon is still spinning though indicating it's loading something. After about ~30 seconds of waiting the module finishes loading.

Steps to reproduce: Browser/OS used is Windows 7 and IE 11.0.9600.16428 (issue does not occur on Windows 8) and I noticed it only happens when using the new default "Edge" document mode of IE11. When I switch Document mode to 10 in developer console, the SCORM module loads fine. Happens once you click the 'Enter' button and /mod/scorm/loadSCO.php is called with arguments to start loading the SCORM package.

The issue occurs on our new 2.5.3 test Moodle site, on our old 2.2.9 production site and on a test Moodle 2.5 site used by a vendor to create our 2.5.3 theme. SCORM Packages on our sites that were tested were produced with Lectora 11.1, Lectora 10.6 and it is also showing up on the vendor test site on the "Features Demo" course, when clicking on the "eXe SCORM Package". It also occurs when using the default Moodle themes, so it does not appear to be theme-related.

Additional notes:
Doing some additional testing with Fiddler 2 running to examine the web traffic, it shows /mod/scorm/loadSCO.php?a=etc.. starts loading, sending only the headers and 0 content length. It then completes loading 30 seconds later and returns the LoadSCO content and populates the 'box' of the SCORM package correctly.