I literally had this happen with my desktop last night, and it’s entirely down to Windows actively choosing to go into sleep mode or not. No activity on the computer, click on sleep, the monitors go off and I started to walk away except I noticed that my keyboard and mouse were still on (the first things to turn off when Windows goes to sleep for me) and the fans were still running. Wiggled the mouse and it had only turned the monitors off. I tried it 2 or 3 more times and Windows kept doing the same thing - putting the monitors to sleep and nothing else. I eventually just straight up shut it down with the power button.
I literally had this happen with my desktop last night, and it’s entirely down to Windows actively choosing to go into sleep mode or not. No activity on the computer, click on sleep, the monitors go off and I started to walk away except I noticed that my keyboard and mouse were still on (the first things to turn off when Windows goes to sleep for me) and the fans were still running. Wiggled the mouse and it had only turned the monitors off. I tried it 2 or 3 more times and Windows kept doing the same thing - putting the monitors to sleep and nothing else. I eventually just straight up shut it down with the power button.