Heard about this this morning but seemed to be fine on Developer Edition. Just lost them :(. Might try that about:config workaround.
Brinkmann delivers the goods.
Mozilla started to roll out a fix for Release, Beta, and Nightly versions of Firefox. The fix uses Mozilla Studies, and you need to make sure that this is enabled to get it.
Interesting fix, to say the least.
There is another solution linked at Mozilla Add-on Certificate Error Disables Noscript and HTTPSEverywhere on Tor Browsers which is about the same issue.
There is also a method that allows you to quickly load the fix via studies:
This is what worked for me (with the linked app.normandy.first_run edit).