in browser console I see a counter warning or error maybe(i have disabled your script for now so i cant check it right now) that says counter not found, i think. its in the updater counter code of your script which i think its somebody else code ,right?
it populates the browser console and even disabling your script wont remove it right away. i disabled your script and restarted firefox and it doesn't appear anymore.

this addon causes some https://addons.mozilla.org addons js to malfunction like this page https://addons.mozilla.org/en-US/firefox/addon/youtube-anywhere-player/ that clicking on image previews would redirect to picture address instead of popup preview.
also the update counter is always counting even though the addon is disabled?