It keeps happening. Find the kernel and xfce4-session versions below.

$ cat /proc/version
Linux version 5.4.0-62-generic (buildd@lgw01-amd64-045) (gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)) #70-Ubuntu SMP Tue Jan 12 12:45:47 UTC 2021

$ xfce4-session --version
xfce4-session 4.14.2 (Xfce 4.14)

$ cat .xsession-errors
dbus-update-activation-environment: setting DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
dbus-update-activation-environment: setting DISPLAY=:0
dbus-update-activation-environment: setting XAUTHORITY=/home/vegeta/.Xauthority
dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
dbus-update-activation-environment: setting SHELL=/bin/bash
dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
dbus-update-activation-environment: setting XDG_CONFIG_DIRS=/etc/xdg/xdg-xubuntu:/etc/xdg
dbus-update-activation-environment: setting XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session0
dbus-update-activation-environment: setting CLUTTER_BACKEND=x11
dbus-update-activation-environment: setting LANGUAGE=en_US
dbus-update-activation-environment: setting DESKTOP_SESSION=xubuntu
dbus-update-activation-environment: setting PWD=/home/vegeta
dbus-update-activation-environment: setting XDG_SESSION_DESKTOP=xubuntu
dbus-update-activation-environment: setting LOGNAME=vegeta
dbus-update-activation-environment: setting QT_QPA_PLATFORMTHEME=gtk2
dbus-update-activation-environment: setting XDG_SESSION_TYPE=x11
dbus-update-activation-environment: setting GPG_AGENT_INFO=/run/user/1000/gnupg/S.gpg-agent:0:1
dbus-update-activation-environment: setting XAUTHORITY=/home/vegeta/.Xauthority
dbus-update-activation-environment: setting XDG_GREETER_DATA_DIR=/var/lib/lightdm-data/vegeta
dbus-update-activation-environment: setting GDM_LANG=en_US
dbus-update-activation-environment: setting HOME=/home/vegeta
dbus-update-activation-environment: setting IM_CONFIG_PHASE=1
dbus-update-activation-environment: setting LANG=en_US.UTF-8
dbus-update-activation-environment: setting XDG_CURRENT_DESKTOP=XFCE
dbus-update-activation-environment: setting XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
dbus-update-activation-environment: setting XDG_SESSION_CLASS=user
dbus-update-activation-environment: setting GTK_OVERLAY_SCROLLING=0
dbus-update-activation-environment: setting USER=vegeta
dbus-update-activation-environment: setting DISPLAY=:0
dbus-update-activation-environment: setting SHLVL=1
dbus-update-activation-environment: setting XDG_RUNTIME_DIR=/run/user/1000
dbus-update-activation-environment: setting XDG_DATA_DIRS=/usr/share/xubuntu:/usr/share/xfce4:/usr/local/share:/usr/share:/var/lib/snapd/desktop
dbus-update-activation-environment: setting PATH=/home/vegeta/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
dbus-update-activation-environment: setting GDMSESSION=xubuntu
dbus-update-activation-environment: setting DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
dbus-update-activation-environment: setting _=/usr/bin/dbus-update-activation-environment
/usr/bin/iceauth:  creating new authority file /run/user/1000/ICEauthority

(xfce4-session:1694): xfce4-session-WARNING **: 09:11:37.089: xfsm_manager_load_session: Something wrong with /home/vegeta/.cache/sessions/xfce4-session-x1:0, Does it exist? Permissions issue?
xfwm4-Message: 09:11:37.210: Prefer XPresent with Mesa Intel(R) UHD Graphics (CML GT2)

** (wrapper-2.0:1880): WARNING **: 09:11:37.541: No outputs have backlight property

(wrapper-2.0:1874): GLib-GIO-CRITICAL **: 09:11:37.560: g_file_new_for_path: assertion 'path != NULL' failed

(wrapper-2.0:1874): GLib-GIO-CRITICAL **: 09:11:37.560: g_file_monitor_file: assertion 'G_IS_FILE (file)' failed

(wrapper-2.0:1874): GLib-GObject-WARNING **: 09:11:37.560: invalid (NULL) pointer instance

(wrapper-2.0:1874): GLib-GObject-CRITICAL **: 09:11:37.560: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed

(wrapper-2.0:1874): Gtk-WARNING **: 09:11:37.560: Attempting to add a widget with type GtkToggleButton to a container of type XfcePanelPlugin, but the widget is already inside a container of type XfcePanelPlugin, please remove the widget from its existing container first.

(wrapper-2.0:1871): Gtk-WARNING **: 09:11:37.580: Negative content width -3 (allocation 1, extents 2x2) while allocating gadget (node button, owner GtkToggleButton)

(wrapper-2.0:1872): Gtk-WARNING **: 09:11:37.584: gtk_widget_size_allocate(): attempt to allocate widget with width -1 and height 22

(wrapper-2.0:1874): Gtk-WARNING **: 09:11:37.606: Negative content width -3 (allocation 1, extents 2x2) while allocating gadget (node button, owner GtkToggleButton)

(wrapper-2.0:1880): Gtk-WARNING **: 09:11:37.629: Negative content width -3 (allocation 1, extents 2x2) while allocating gadget (node button, owner PowerManagerButton)

(wrapper-2.0:1883): Gtk-WARNING **: 09:11:37.746: Negative content width -3 (allocation 1, extents 2x2) while allocating gadget (node button, owner PulseaudioButton)

ERROR: NVIDIA driver is not loaded


(polkit-gnome-authentication-agent-1:2114): GLib-CRITICAL **: 09:11:37.793: g_variant_new_string: assertion 'string != NULL' failed

ERROR: Unable to load info from any available system


(polkit-gnome-authentication-agent-1:2114): polkit-gnome-1-WARNING **: 09:11:37.793: Failed to register client: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files

** (xfce4-screensaver:2111): WARNING **: 09:11:37.825: screensaver already running in this session