An unknown number of Apple Silicon users who have two or more accounts on their M1 Mac are seeing their screensaver spontaneously start and them being logged out.
Apple's Fast User Switching — introduced in 2003's OS X Panther, and a convenient security feature — is reportedly causing problems with some M1 Macs. The feature lets users have more than one login account on their Mac, including a Guest one, and switch between them. However, that switching feature is reportedly activating unexpectedly.
What happens is that a user can be working at their Mac when, without prompting, it displays a screensaver — and logs the user out. More, it's not possible to clear the screensaver unless you: