X-Session killed / forced log-out after suspend

[Karl Kastner]

X-sessions on my system are killed or automatically logged out when I suspend from resume.

Steps to reproduce:

gnome-screensaver-command --lock & systemctl suspend -i

Wait for system to suspend.
Disconnect, power, external monitor and usb devices.
Resume by pressing the power button.
Be greeted by a new log-in screen.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: systemd 234-2ubuntu12.2
Uname: Linux 4.15.0-041500rc6-generic x86_64
NonfreeKernelModules: nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.7-0ubuntu3.7
Architecture: amd64
CurrentDesktop: GNOME
Date: Sat Mar 3 18:34:21 2018
InstallationDate: Installed on 2015-11-05 (849 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
MachineType: Notebook W230SS
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-041500rc6-generic root=/dev/sda3 ro uveau.modeset=0 acpi_enforce_resources=lax nosplash uveau.modeset=0 acpi_enforce_resources=lax acpi_enforce_resources=lax
SourcePackage: systemd
UpgradeStatus: Upgraded to artful on 2018-01-16 (46 days ago)
dmi.bios.date: 04/15/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 4.6.5
dmi.board.asset.tag: Tag 12345
dmi.board.name: W230SS
dmi.board.vendor: Notebook
dmi.board.version: Not Applicable
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 9
dmi.chassis.vendor: Notebook
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr4.6.5:bd04/15/2014:svnNotebook:pnW230SS:pvrNotApplicable:rvnNotebook:rnW230SS:rvrNotApplicable:cvnNotebook:ct9:cvrN/A:
dmi.product.family: Not Applicable
dmi.product.name: W230SS
dmi.product.version: Not Applicable
dmi.sys.vendor: Notebook
modified.conffile..etc.systemd.resolved.conf: [modified]
mtime.conffile..etc.systemd.resolved.conf: 2017-11-16T19:29:56.550129