All links in Bitbucket site needs to be clicked twice using Firefox

Recently (2-3 weeks ago?) bitbucket.org started behaving strange.

• If I start FF with bitbucket in a tab, it won't load and the address bar is blank. The favicon is still there, though.
• Almost everytime I click a link within Bitbucket, nothing happens. Clicking the second time works. Opening a link in a new tab or window produces a blank tab. Opening the link in another tab again works.

Different things I tried to resolve it:

• I have tried FF26 and 27
• Safe mode (that is, no addons)
• Clear cache, cookies etc
• Reset FF (which made me have to install all the addons again )

One thing I'm wondering, is if you've started using some JS library for click tracking or something? Or updated one recently?