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
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/ dbus-1/ services/ org.kde. plasma. Notifications. service \ share/dbus- 1/services/ org.kde. plasma. Notifications. service
ln -s /usr/share/
~/.local/