Mojave screen saver starts randomly I have a new Mojave (10.14.1) installation on an iMac (Retina 5K, 27-inch, 2017).  My screen saver is set to start after 5 minutes.  I have a hot corner defined to start the screen saver.

I have noticed that periodically, the screen saver just starts up out of the blue.  Typically this happens while I am scrolling with the magic mouse.  I am definitely not hitting the hot corner.

Any suggestions for why this is happening and how to stop it?
It turns out another Mac had an idle screen sharing session open to this computer.  After closing that, I have not experience the screen saver start.