Display Brightness Resets with Most OS Updates

Hello, all.

It seems that with most, but not all, OS updates the display brightness setting on my 27" iMac gets reset to default full.

The problem is, it needs to be calibrated at a lower level for my work. Sometimes I catch it but sometimes, like when I'm very busy, I don't.

All automatic adjustment settings are set to off and the calibrated profile is properly saved. In fact, it typically stays on the saved calibrated setting with the only exception being the brightness fader.

Any ideas?