The site http://perceptive.nathan/supportarea/account/index.php, has a bug - page A redirecting to page B which is redirecting back to A; which creates an infinite cycle. I am not sure though why you are facing this only in FF; it may be that FF is triggering a condition, which brings the site bug to surface. I would say that the site still has a bug.
Additionally, doesn't FF complain after a while that it has detected that the call would never succeed? It usually is able to detect cycles of redirected and breaks off the chain early enough.