Guest User password?

The Guest User account on our Mac has started requiring a password. I don't know when this started but I'm guessing that it was when we installed Catalina. I have no idea what password is required. When I go into Users & Groups (in System Preferences), I see nothing relating to a password for the Guest User account. Indeed, the text displayed in that pane, explicitly states (see the screenshot below):

Logging in to the guest account does not require a password.

Any ideas?

Thanks