Additional users are reporting this issue on Chromebook Central.
https://productforums.google.com/forum/#!topic/chromebook-central/qZkd1BfNafQ
also, possibly this report
https://productforums.google.com/forum/#!topic/chromebook-central/l-L_4grr0Vs

Feedback report is http://listnr/product/208/report/85669595600.

...
162 | 2018-09-18 16:41:28 | System boot | 101
163 | 2018-09-18 16:41:28 | System Reset
164 | 2018-09-18 16:45:51 | ACPI Enter | S3
165 | 2018-09-18 16:46:27 | ACPI Wake | S3
166 | 2018-09-18 16:46:27 | Wake Source | GPE # | 0
167 | 2018-09-18 16:47:05 | Kernel Event | Clean Shutdown
168 | 2018-09-18 16:47:05 | ACPI Enter | S5
169 | 2018-09-18 16:47:06 | System boot | 102
170 | 2018-09-18 16:47:06 | ACPI Wake | S5
171 | 2018-09-18 16:47:06 | Wake Source | Power Button | 0
172 | 2018-09-18 16:48:20 | ACPI Enter | S3
173 | 2018-09-18 16:48:53 | ACPI Wake | S3
174 | 2018-09-18 16:48:53 | Wake Source | GPE # | 0
175 | 2018-09-18 16:49:07 | Kernel Event | Clean Shutdown
176 | 2018-09-18 16:49:08 | ACPI Enter | S5
177 | 2018-09-18 16:49:09 | System boot | 103
178 | 2018-09-18 16:49:09 | ACPI Wake | S5
179 | 2018-09-18 16:49:09 | Log area cleared | 1031
180 | 2018-09-18 16:49:09 | Wake Source | Power Button | 0

powerd.PREVIOUS:

...
[0918/164818:INFO:suspender.cc(457)] Starting suspend
[0918/164818:INFO:main.cc(267)] Running "/usr/bin/powerd_setuid_helper --action=suspend  --suspend_wakeup_count_valid --suspend_wakeup_count=4"
[0918/164853:INFO:daemon.cc(636)] powerd_suspend returned 0
[0918/164853:INFO:suspender.cc(416)] Finishing request 58851329 successfully after 36s
[0918/164853:INFO:internal_backlight_controller.cc(734)] Setting brightness to 2895 (63%) over 0 ms
[0918/164853:INFO:daemon.cc(464)] Lid opened
[0918/164853:INFO:input_device_controller.cc(286)] Configuring devices for mode "laptop"
[0918/164853:INFO:input_device_controller.cc(217)] Un-inhibiting /sys/devices/platform/80860F41:00/i2c-0/i2c-ELAN0000:00/input/input6
[0918/164853:INFO:input_device_controller.cc(217)] Un-inhibiting /sys/devices/platform/i8042/serio0/input/input5
[0918/164853:INFO:input_device_controller.cc(205)] Enabling wakeup for /sys/devices/platform/80860F41:00/i2c-0/i2c-ELAN0000:00/input/input6 through /sys/devices/platform/80860F41:00/i2c-0/i2c-ELAN0000:00
[0918/164853:INFO:daemon.cc(750)] On battery at 98% (displayed as 100%), 2.806/2.876Ah at 0.127A, 0s until empty (calculating)
[0918/164858:INFO:daemon.cc(750)] On battery at 98% (displayed as 100%), 2.806/2.876Ah at 0.241A, 7h55s until empty (6h43m40s until shutdown)
[0918/164903:INFO:daemon.cc(473)] Power button down
[0918/164903:INFO:main.cc(248)] Launching "sync"
[0918/164905:INFO:daemon.cc(972)] Got RequestShutdown message from :1.9 with reason user-request (UI request from ash: power button)
[0918/164905:INFO:display_power_setter.cc(81)] Asking DisplayService to turn all displays off
[0918/164905:INFO:internal_backlight_controller.cc(734)] Setting brightness to 0 (0%) over 0 ms
[0918/164905:INFO:daemon.cc(1191)] Shutting down, reason: user-request
[0918/164905:INFO:main.cc(248)] Launching "/usr/bin/powerd_setuid_helper --action=shut_down --shutdown_reason=user-request"
[0918/164905:INFO:suspend_delay_controller.cc(75)] Unregistering suspend delay 58851329 (shill) on behalf of :1.8
[0918/164905:INFO:suspend_delay_controller.cc(75)] Unregistering dark suspend delay 58884097 (shill) on behalf of :1.8
[0918/164905:INFO:daemon.cc(1136)] Session state changed to stopped
[0918/164905:INFO:state_controller.cc(916)] Updated settings: dim=5m screen_off=5m30s lock=0s idle_warn=0s idle=6m30s (suspend) lid_closed=suspend use_audio=1 use_video=1 wake_locks=
[0918/164905:INFO:daemon.cc(1095)] Received updated external policy: ac_dim=7m ac_screen_off=7m30s ac_lock=0s ac_idle_warn=0s ac_idle=30m battery_dim=5m battery_screen_off=5m30s battery_lock=0s battery_idle_warn=0s battery_idle=6m30s ac_idle=suspend battery_idle=suspend lid_closed=no-op use_audio=1 use_video=1 presentation_factor=2.0 user_activity_factor=2.0 wait_for_initial_user_activity=0 force_nonzero_brightness_for_user_activity=1 (Prefs)
[0918/164905:INFO:state_controller.cc(916)] Updated settings: dim=5m screen_off=5m30s lock=0s idle_warn=0s idle=6m30s (suspend) lid_closed=no-op use_audio=1 use_video=1 wake_locks=
[0918/164906:INFO:suspend_delay_controller.cc(121)] Unregistering suspend delay 58851330 (chrome) due to D-Bus client :1.9 going away
[0918/164906:INFO:suspend_delay_controller.cc(121)] Unregistering dark suspend delay 58884098 (chrome) due to D-Bus client :1.9 going away
EOF

Looks like userspace resumed successfully. Might be a display issue?

I am getting the same thing on Nautilus
Chrome OS - 69.0.3497.95 (Official Build) (64-bit)
Firmware - Google_Nautilus.10431.71.0
Version - 10895.56.0
ARC - 5006116
Flash - 31.0.0.108 

Reported a similar issue from M67. Correct me if it is a different issue.

https://bugs.chromium.org/p/chromium/issues/detail?id=859358

Same issues. What I'm finding is that it only happens to me when I wake from sleep within about 2 minutes from sleep. Maybe something hasn't fully went to sleep prior from waking? 

@#5, does seem like same issue ... certainly same regression (black screen).

I don't see anything particularly interesting in syslog w/ regard to gpu/display.  Hunting around the suspend I do see some error messages w/ regard to wifi/BT,

  2018-09-18T16:48:53.405835-04:00 ERR shill[1130]: [ERROR:wifi.cc(970)] Disconnected due to inability to connect to the service.
  2018-09-18T16:48:53.473843-04:00 NOTICE powerd_suspend[2871]: Enabling Bluetooth HCI mode change event after resume
  2018-09-18T16:48:53.504643-04:00 NOTICE powerd_suspend[2885]: hcitool failed with exit status 1
  2018-09-18T16:48:53.513572-04:00 NOTICE powerd_suspend[2891]: Resume finished
  2018-09-18T16:49:05.754708-04:00 ERR shill[1130]: [ERROR:object_proxy.cc(582)] Failed to call method: fi.w1.wpa_supplicant1.Interface.Disconnect: object_path= /fi/w1/wpa_supplicant1/Interfaces/1: fi.w1.wpa_supplicant1.NotConnected: This interface is not connected
  2018-09-18T16:49:05.754744-04:00 ERR shill[1130]: [ERROR:dbus_method_invoker.h(112)] CallMethodAndBlockWithTimeout(...): Domain=dbus, Code=fi.w1.wpa_supplicant1.NotConnected, Message=This interface is not connected
  2018-09-18T16:49:05.754773-04:00 ERR shill[1130]: [ERROR:chromeos_supplicant_interface_proxy.cc(196)] Failed to disconnect: fi.w1.wpa_supplicant1.NotC

While I'd hope they are unrelated to waking the display I'll note them for now in hopes of at least understanding why they are there.

If someone on the thread has a reliable repro ... might be worth trying it w/ wifi & bluetooth turned off to see if it has any positive impact.

Same issue on Kefka 
Chrome OS: 69.0.3497.95 
Firmware: Google_Kefka.7287.379.0
Version: 10895.56.0
ARC: 5006116
Flash: 31.0.0.108

We have this issue as well with some 4 year old Dell Chromebooks but not our newer ones. 

Do using the brightness keys result in the display turning back on?