This issue resolved itself later on when I completed the upgrade by running sudo apt-get -f install, which I was required to do anyway due to manually installed custom packages, and as far as I can tell this "bug" didn't, in fact, cause any real problems.
** Changed in: firefox (Ubuntu) Status: Incomplete => Invalid -- package firefox-2 None [modified: /var/lib/dpkg/info/firefox-2.list] failed to install/upgrade: https://bugs.launchpad.net/bugs/214078 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs