New
#280
Just to verify in case this may be at startup, do you have Users must enter a user name and password to use this computer checked in netplwiz?
Sign in User Account Automatically at Windows 10 Startup | Tutorials
Yep, that's the one.
Well, it looks like you have everything set properly to require you to sign in after 20 minutes of being idle.
That does seem like it would be related.
As a test, are you able to manually lock the computer using Win+L?
Correct.
You could try a repair install to see if it may sort it without losing anything.
Repair Install Windows 10 with an In-place Upgrade | Tutorials