Power button slowly pulsing, won't wake up from sleep. HP Spectre x360

[AndyB1234566]

Brand new, setup windows 10, then once complete left it charging with the screen closed, 2 hours later, very warm, opened, slow pulsing power button LED. Wouldn't wake up - only thing that worked was holding down for 5+ seconds to do a hard restart.

Once rebooted, with power out, closing lid, leaving for a while, then opening, all is fine. Never seems to go wrong if the power isn't connected at all.

Charging with the lid left open seems ok too. 

But if charging and I close the lid and leave it a while, then come back to it, same pulsing problem, reset required.

Seems to happen if I close the lid then put the power in and leave it.

Also, when this happens, it doesn't seem to charge.

Subsequently went through all the troubleshooting/upgrade steps on https://h30434.www3.hp.com/t5/Notebooks-Knowledge-Base/HP-laptops-Sleep-mode-issues-in-Windows-10/ta....

This included the HP Support Assist updates. (Only suggested one update - WLAN).

Ideas? Other than that, nice machine.

[AndyB1234566]

So today I just left it running on the desk without shutting the lid, power plugged in. Came back to it a couple of hours later and the same thing had happened. Unresponsive, slowly pulsing LED on the power button, wouldn't turn back on without a long press to reset.

It's not really something I'd expect of a brand new machine.

[AndyB1234566]

So following a support call I'm having the laptop replaced, but for the record I just wanted to share the results of my latest tests.

The problem has nothing to do with charging. I can get the failure to occur solely on battery power.

First, the support agent told me that the slow pulsing is supposed to indicate sleep mode. 

So, while the laptop is on, if I press the power button for a couple of seconds to sleep the machine, it doesn't seem to work. If I close the laptop lid and open it again, the laptop seems not to have gone asleep.

If, with the laptop on, I choose sleep from the power menu without closing the lid, the laptop goes to sleep and I get the slow pulsing.

Then, if I try to wake it up by pressing the power button, nothing happens (either with a quick press or holding it down a couple of seconds) - I can try it many times - it won't wake up. The only thing that works is a long press (+5 seconds?) to cause a hard reset.

Quite repeatable, in case anyone gets the chance to troubleshoot the returned device.