I have exactly the same problem as somebody else posted today, an intermittent black screen (going black for about 3 or so seconds, then returning).
I have a lot of computer hardware around, so I could run some tests.
Noticed it first maybe five weeks ago, when I had my first gaming session on it. I turned it on again about two weeks ago, and had the problem within a minute.
Today I have tried it on two top of the range separate monitors of different brands that I know work perfectly (both running 4k) using different HDMI cables.
I have used it with wired and Bluetooth mouse and keyboards. The same problem with all. I have unplugged the other USB devices I had connected (A conferencing device), and same problem.
I have tried from different parts of the house (so different power supply outlets). Still the same problem. That said I have used it in my office and laptop and main computer are on there over 10 hours a day with no issues.
I have tried it with an alternative usb-c power supply, and the same problem.
On my side, I used the device for weeks absolutely fine with no problems in maybe 40 hours. I did change some of the bios settings when it first arrived, but it worked without any problems at all with those settings, and I did not change the graphics memory, and no other settings were changed since.
It is windows 11, and I have automatic updates turned on. When the screen goes black it is for about three seconds.
I can not track the problem down to a specific action, it may be within a couple of minutes of starting up, or playing a simple low requirement game.
Timings are hard to place, had it showing three times within a couple of minutes of booting today, then have just used it for half an hour and has been fine.
