lp:1477106 is another bug where this is being discussed (but didn't get much attention). I agree that this is due to somewhat broken behaviour of gtk3 and not cups-filter or avahi. In any case, an updated GTK 3 patch for Focal is available in the following for those who came here with this problem:
https://launchpad.net/~launchpad-weyland/+archive/ubuntu/libgtk3-no- avahi/ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1753509 Title: avahi-daemon adds/installs every printer on network To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cups-filters/+bug/1753509/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
