We just moved our JIRA server around on our internal network, but nothing changed on the server configuration as best we can tell. Yesterday before the move, issues displayed fine in all browsers (most of us use Chrome as the default browser, some use Firefox, and a few use Safari). Now, after the move, all non-IE browsers have major display problems on issue pages:

On IE 10, it looks totally normal. I ran the Chrome developer tools and no errors appear in the Network logs. A few messages appear in the Console:
***** Analytics log [kickass.criteriaAutoUpdateEnabled][{"enabled":true,"context_pageSession":"c43n2nslmims4ivny7yhy8e7trcnmi","context_pageTime":1}] batch.js:12
Your are trying to create a ToggleBlock with selector '.twixi'.One already exists with this trigger so has been ignored. batch.js:3385
Your are trying to create a ToggleBlock with selector '.toggle-trigger'.One already exists with this trigger so has been ignored. batch.js:3385
Your are trying to create a ToggleBlock with selector '.toggle-trigger'.One already exists with this trigger so has been ignored. batch.js:3385
I've cleared my cache, restarted Chrome, run in Incognito mode, etc., and the results are always as seen above. The same goes for Safari, Firefox, and Opera (actually it's even more messed up in Opera: the blue menu bar there occupies space from the top of the screen to the bottom!).
This is on JIRA v6.0.4#6100 with a number of add-ons, including JIRA Agile and Zephyr. I can provide any more specific information that might help debug the issue, just let me know.
Thanks!