Who I have the same questioned this topic

Interesting little glitch occurring.   The brightness of my screen keeps bouncing from my brightness setting to very dim.  No changes in location; it can just be sitting on my desk and the brighter screen will go dim for a few minutes, then brighten back up again with no interference on my part.  Has done this at least a half dozen times already. 

Changing the brightness setting doesn't correct the issue and in fact, the brightness setting itself doesn't always take immediate effect even when I force a change.

Any ideas?