Got it sorted. While running dev tools I saw it was in emulation mode for IE 7. I switched it back to normal and everything works now. No clue how or why it would be set that way, but thanks for your help and sorry for wasting your time on this!
One thing to note is that Sharepoint may well force your client browser into emulation mode via headers, so check that if you start looking at it on the CMS version.
