Comment 20 for bug 1774950

I'm having the exact same problem in a clean installation of Ubuntu 18.04.
I'm on a Lenovo Legion Y720. Even suspending by command or by closing the lid, it hangs. I can see a dash blinking in top left of the screen. In that stage, the laptop is not completely dead: the numlock button stills toggles the numlock led. But when I hit ctrl-alt-F1, then the blinking dash disappears and numlock button doesn't even work any more. From then, I have to hard reset the machine. My logs look just like the OP described, so the machine actually thinks it went to sleep.
It's odd that it doesn't happen all the time. Sometimes it suspends correctly.
I'm using nVidia drivers. Some said that driver might be the problem, although some people report having the same problem with intel cards.
Not sure if related, but I got LOTS of these on dmesg:

[dom jun 10 20:55:04 2018] pcieport 0000:00:1c.4: PCIe Bus Error: severity=Corrected, type=Data Link Layer, id=00e4(Transmitter ID)
[dom jun 10 20:55:04 2018] pcieport 0000:00:1c.4: device [8086:a114] error status/mask=00001000/00002000
[dom jun 10 20:55:04 2018] pcieport 0000:00:1c.4: [12] Replay Timer Timeout

Also, in those cases where it actually suspends ok, sometimes it randomly wakes up as if someone would have opened the lid (many times I double checked it was actually suspended before putting the laptop in my backpack and then found it freakingly hot because it turned on by itself).

I'm running Ubuntu on Samsung SSD 850 Pro and I also have a WD Black M.2 on the pci express slot with a different SO.