I think (not positive) that its a software issue, I've noticed it happening at the same time with my smart actions changing. The SA I use the most is set to turn screen on 10% whenever wifi comes on, so when I turn wifi off it goes back to auto brightness. Well if I sit and watch it change / turn that action off, it sits on 10% brightness until I lock/unlock the phone. It also does this when i turn the back on (in other words it stays on whatever brightness it was on AFTER THE 10% rule is activated UNTIL I lock/unlock the screen).
I uninstalled the SmartActions I restarted the phone but the screen is the same problem. Just when you unlock the phone or finish a call the screen returns to the intensity at which it should be.
I think that it's not a hardware problem because the light sensor works but only when the screen increases its intensity.
What do you think, what tips do you give me? I see that there are others who have this problem ...
Thank you again!