Comment by MrDOS

Nah, it's Firefox, not the ad blocker. I run into similar problems all the time, and disabling my ad blocker never solves it. If you pop open the developer console and look for errors, it usually boils down to Firefox having stricter policies about cross-origin requests. Even major web properties simply don't bother testing for even the most superficial functionality on browser engines other than Blink any more.