Just took a look on the KDE bug site, and this has been reported. If you set the power management pref to turn the screen off BEFORE the screensaver blanks the screen (and locks it), then everything works!
Just took a look on the KDE bug site, and this has been reported. If you set the power management pref to turn the screen off BEFORE the screensaver blanks the screen (and locks it), then everything works!