Rated 3 out of 5 stars
When I check for new addons I never been notifed there was an update to 3.1.14 for Update Scanner.
FF 27 and I went back to 3.1.13 and turned off any update checks and that version is working well for me.
Which version do you have installed? This is a Firefox bug - please report at forums.mozillazine.org or https://bugzilla.mozilla.org/