ubiquity doesn't do anything in the live session, it's the installer app that starts if you click the corresponding icon once in the live session, reassigning to gnome-settings-daemon which is a more likely starting point to investigate the issue
Do you know when it started exactly? gnome-settings/gnome-shell got updated to the new 3.29 serie a bit before you opened that report
ubiquity doesn't do anything in the live session, it's the installer app that starts if you click the corresponding icon once in the live session, reassigning to gnome-settings- daemon which is a more likely starting point to investigate the issue
Do you know when it started exactly? gnome-settings/ gnome-shell got updated to the new 3.29 serie a bit before you opened that report