Screen is doing that sweet thing where the backlight never turns off

[t0adman]

I had this issue once before and found that the settings had mysteriously changed without my touching them. I've since checked them and made sure they were all correct (see image). Sure enough my device will no longer turn off while plugged into the power, PC or not plugged in at all. Hard on battery life. Any suggestions? Should this be in the "Why I want to kill my Imagio" thread?