Lately my Macbook Pro switches to the "Lock Screen" page out of nowhere while I am working. When I say "while I am working" I want to make clear it's not due to inactivity, I am actually using the computer as it happens.
It does not log me out (none of my windows are closed), it only locks.
I've noticed it happens usually shortly after I've logged in. So for example it's morning, I login start doing things then a few seconds later I'm locked out. I log back in, and again a few seconds later I'm locked out. It happens 2 or 3 times before it quiets down.
macOS High Sierra 10.13.4