That kind of stuff happens sometimes, not sure why, probably a Firefox issue. Thanks for troubleshooting yourself, and glad you like it :)

Edit: turns out this is indeed a systemic issue, most Firefox users will probably face it. It's essentially caused by a difference between Chrome and Firefox, leading to a mistaken assumption that got into the previous version's code, which creates a compatibility issue in stored data now. The solution is to uninstall and reinstall as MbahDjoe and others have done. Sorry for the inconvenience.