Comment 35 for bug 307306

This is most easily reproducible if you have a laptop, remove / insert the AC lead, and wait some seconds before gnome-power-manager notices, and starts to fade the backlight brightness between its AC and battery presets.

Killing gnome-settings-daemon fixes the issue (or patching it as above).

Since you're assigned to this, I'll not take the liberty of resetting the "Fix relesaed" status, but would suggest it might want to go back to "Confirmed"?