My WIN8.1 that was converterd to WIN 10 does the same thing... Worked ok at first than later on started doing this.
I thought for awhile it had something to do with me using dual monitors with it as it seems to work normal if I am only working my my DELL LAPTOP using its lid monitor. Sometimes it shuts down down normal after hitting the screen POWER OFF using the mouse.
My normal way of powering up is to raise the LAPTOP lid and hit the start button and I usually let it boot to the LOGIN Screen then close the laptop lid. This then powers up both my dual monitors with the MON 1 having the login screen on it. then I log-in from my console setup here...
Sometimes doing it this way I have to riase the laptop lid up and then back down again as my resolutions settting started up wrong for the two monitors... Most of the time it works great..
I also have never waited it out. Will have to try that the next time I shut down with the mouse click. Some one awahile back suggested to do the SHUTDOWN settings again from the control panel and resave them and shut down immediately after making the changes... I tried this and it worked normal for one time haha... Then after turning all back on the next morning it went right to having me open my laptop lid and pushing the main power off button to power down after the mouse click on the power down feature on the screen...
Roy Ken