Glyphicons and other icon fonts don't show up in Internet Explorer after page refresh

Question

I'm totally stumped on this problem (the app in question uses Bootstrap and Backbone):

• when you first load the app after logging in the glyphicons and other icon fonts show up on the page fine.

• on subsequent page loads they don't show up at all. But you can log out and log back in and they show up again.

• it only happens in Internet Explorer. Chrome/FF/Safari are fine.

• it doesn't happen if you go to a part of the app that doesn't require authentication

The same part of the app with (top) and without icons (bottom):

Unfortunately to see the problem it requires authentication so here is that info (you will be redirected to the app):

https://voicethread.com/login/

username: ietest@voicethread.net

pass: orange4

Answer 1

This appears to be fixed, as of /rev/353fe835. While not sending the proper MIME type was indeed a problem, it didn't appear to be the problem.

Instead, the issue appeared to be the no-cache headers. When not allowing cache, IE was not displaying those glyph icons in certain cases. Related posts: 1, 2, and 3.