This was reported in Bug 440223 as part of a crash. The crash when you discard the (nonexistent) unsaved changed has been fixed, but the KCM is still inappropriately marked as dirty when you open it and make no changes.
Correction: it gets marked as dirty once, the first time I open it. If I discard or save the (seemingly nonexistent) changes, it is not marked as dirty again.
Perhaps another data point: on the first launch where it gets inappropriately marked as dirty, it takes a long time to load--like 5 seconds. On subsequent launches after saving or discarding the changed, it is not marked as dirty and loads quickly.
I can't reproduce either issue :(
Just reproduced both again myself, actually. Clicking on the configure button in the Battery & Brightness applet seems to do it quite reliably for me.
Cannot reproduce anymore.