For years, I've had periodic problems with KDE on Arch Linux failing to lock the screen after the configured timeout. This has happened on multiple machines. I'm not sharing configuration between them, nor have I done any customization of KDE outside of things in the settings window. Quite often, when I leave the machine, I'll find it still wide open hours later. This is a serious security issue.

Settings -> Screen Locking -> Lock Screen Automatically is checked and set to 5 minutes.

How can I go about debugging this issue? I.e. is there any sort of log that will show the timer resets, ideally with the reason? Is there a way to verify that the timer is even running?

Same problem by the way