Just got the same, shortly after I logged in, I opened VirtualBox (haven't started the VM yet), then Google Chrome -> went to my mails and ... just got logged out of my session!

Ubuntu 18.04; gnome-session-bin 3.28.1-0ubuntu3.


Logs:
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Jan 08 10:21:27 REDACTED gnome-session[4856]: gnome-session-binary[4856]: WARNING: Application 'org.gnome.SettingsDaemon.Keyboard.desktop' failed to register before timeout
Jan 08 10:21:27 REDACTED gnome-session[4856]: gnome-session-binary[4856]: CRITICAL: We failed, but the fail whale is dead. Sorry....
Jan 08 10:21:27 REDACTED gnome-session-binary[4856]: Unrecoverable failure in required component org.gnome.SettingsDaemon.Keyboard.desktop
Jan 08 10:21:27 REDACTED gnome-session-binary[4856]: WARNING: Application 'org.gnome.SettingsDaemon.Keyboard.desktop' failed to register before timeout
Jan 08 10:21:27 REDACTED gnome-session-binary[4856]: CRITICAL: We failed, but the fail whale is dead. Sorry....
Jan 08 10:21:27 REDACTED virtualbox.desktop[5400]: ICE default IO error handler doing an exit(), pid = 5400, errno = 11
Jan 08 10:21:27 REDACTED bluetoothd[2624]: Endpoint unregistered: sender=:1.107 path=/MediaEndpoint/A2DPSource
Jan 08 10:21:27 REDACTED bluetoothd[2624]: Endpoint unregistered: sender=:1.107 path=/MediaEndpoint/A2DPSink
Jan 08 10:21:27 REDACTED kernel: rfkill: input handler enabled
Jan 08 10:21:27 REDACTED gnome-shell[4958]: gnome-shell: Fatal IO error 0 (Success) on X server :1.
Jan 08 10:21:27 REDACTED polkitd(authority=local)[2802]: Unregistered Authentication Agent for unix-session:3 (system bus name :1.100, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_U
Jan 08 10:21:27 REDACTED at-spi-bus-launcher[4934]: XIO:  fatal IO error 11 (Resource temporarily unavailable) on X server ":1"
Jan 08 10:21:27 REDACTED at-spi-bus-launcher[4934]:       after 145 requests (145 known processed) with 0 events remaining.
Jan 08 10:21:27 REDACTED gsd-power[5096]: gsd-power: Fatal IO error 11 (Resource temporarily unavailable) on X server :1.
Jan 08 10:21:27 REDACTED gsd-wacom[5117]: gsd-wacom: Fatal IO error 11 (Resource temporarily unavailable) on X server :1.
Jan 08 10:21:27 REDACTED gsd-xsettings[5118]: gsd-xsettings: Fatal IO error 104 (Connection reset by peer) on X server :1.
Jan 08 10:21:27 REDACTED gsd-color[5141]: gsd-color: Fatal IO error 11 (Resource temporarily unavailable) on X server :1.
Jan 08 10:21:27 REDACTED gsd-clipboard[5137]: gsd-clipboard: Fatal IO error 11 (Resource temporarily unavailable) on X server :1.
Jan 08 10:21:27 REDACTED gsd-media-keys[5149]: gsd-media-keys: Fatal IO error 11 (Resource temporarily unavailable) on X server :1.
Jan 08 10:21:27 REDACTED gnome-terminal-[5507]: gnome-terminal-server: Fatal IO error 11 (Resource temporarily unavailable) on X server :1.
Jan 08 10:21:27 REDACTED gsd-color[4623]: failed to connect to device: Failed to connect to missing device /org/freedesktop/ColorManager/devices/xrandr_BenQ_Corporation_ZOWIE_XL_LCD_BCH00737SL0_arno_1000
Jan 08 10:21:27 REDACTED systemd[4821]: gnome-terminal-server.service: Main process exited, code=exited, status=1/FAILURE
Jan 08 10:21:27 REDACTED systemd[4821]: gnome-terminal-server.service: Failed with result 'exit-code'.
Jan 08 10:21:28 REDACTED acpid[2618]: client 4841[0:0] has disconnected
Jan 08 10:21:28 REDACTED acpid[2618]: client connected from 3353[0:0]
Jan 08 10:21:28 REDACTED acpid[2618]: 1 client rule loaded
Jan 08 10:21:31 REDACTED gnome-shell[3400]: JS ERROR: TypeError: this._currentWindow is null
                                         _setCurrentRect@resource:///org/gnome/shell/ui/keyboard.js:536:13
                                         wrapper@resource:///org/gnome/gjs/modules/_legacy.js:82:22
                                         _init/<@resource:///org/gnome/shell/ui/keyboard.js:503:13
Jan 08 10:21:31 REDACTED gnome-shell[3400]: JS ERROR: TypeError: this._currentWindow is null
                                         _setCurrentRect@resource:///org/gnome/shell/ui/keyboard.js:536:13
                                         wrapper@resource:///org/gnome/gjs/modules/_legacy.js:82:22
                                         _init/<@resource:///org/gnome/shell/ui/keyboard.js:503:13
Jan 08 10:21:32 REDACTED gnome-shell[3400]: g_array_unref: assertion 'array' failed
Jan 08 10:21:32 REDACTED gnome-shell[3400]: g_array_unref: assertion 'array' failed
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