A setting called “Allow unlocking without password for [time]” can be set in the Screen Locking section in settings, while the unlocking without password will generate a authentication failure, shown in logs, and would be counted as entering wrong passwords (so it will trigger the protection mechanism, and prevent users from logging in to their machines via kscreenlocker lockscreen in several minutes.) This event could be reproduced easily by setting the automatic screen lock to a smaller time limit like 1 minutes, and within the seconds defined previously in that section quickly press the Space key, then it will unlock but an authentication failure will appear in journalctl sys facility 10 (auth.log equivelant).
The distribution I am on is Manjaro Linux; running KDE Plasma on X11. Hardware: x86_64 device.