I have the same issue (using regular Ubuntu 20.04.3 w. KDE and XFCE installed).
Using a workaround stops xfce4-notifyd from starting here: mkdir -p ~/.local/share/dbus-1/services/ ln -s /usr/share/dbus-1/services/org.kde.plasma.Notifications.service \ ~/.local/share/dbus-1/services/org.kde.plasma.Notifications.service -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1914770 Title: Notifications provided by xfce instead of plasma To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/plasma-desktop/+bug/1914770/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs