You can try this:
"A. To check any timers will wake your machine that are in effect, run
You'll get a list of any active wake timers on the system."
On my computer, I had to use an elevated command prompt for it to work.
Right-click on the Start Button and choose "Command Prompt (Admin)"
There's more to try here:
powercfg -waketimers did not show anything at all, so I guess that's good.
powercfg -lastwake said the my Ethernet was the cause for last wakeup.
I followed the advice from How To Prevent Your Computer From Waking Up Accidentally and will see if that does the trick.