I'm running Fedora 45 with KDE Plasma 6.7.1, and the system clock keeps changing to a time that's one hour ahead. Switching date and time settings to manual and then back to automatic temporarily fixes it, although KDE reports that the date and time application has crashed. The clock soon becomes incorrect again. Each time I make this change, the application also asks for my password twice, even when the first password entry is accepted. I'm not dual-booting with Windows, and I'm located in the UK, where the timezone observes daylight saving time and switches between GMT and BST.
2 Answers
Since you’re in the UK, check that the configured timezone is set to a location such as Europe/London rather than a fixed GMT or UTC offset. A fixed timezone would leave the clock exactly one hour wrong during British Summer Time. Also verify that automatic network time synchronization is enabled and that no separate service is repeatedly overwriting the clock.
The repeated password prompt and the date-and-time settings application crashing sound like a KDE authorization or system-settings bug, separate from the timezone itself. Check the selected region and timezone from the command line with `timedatectl`, then confirm that the system reports the correct zone and that NTP synchronization is active. If the zone is correct but the time still changes, inspect the system journal for time-sync services fighting over the clock.
The fact that the difference is exactly one hour makes a daylight-saving or fixed-offset timezone setting more likely than a hardware clock problem. The lack of a Windows installation also rules out the usual dual-boot time conflict.