I did the changes earlier today as suggested by @Mike here - http://xenforo.com/community/threads/litespeed-sends-text-html-with-css-304-responses.54185/ due to my users on Chrome complaining about css errors on the front end.
Should I roll that back and check if the problem continuous in the acp? Oh I'll give that a try. Any other way to find out what's wrong?
Edit: Nope, that change doesn't seem to be the problem. So how do I figure this out?