Ambient Light Sensor `inverted`?

No, it dims so that it doesn't blind you when all the lights are out, so you don't disturb others, and have to worry about changing the brightness if the lights go on an off in a classroom for example. Also it it's bright outside it brightens the screen so you can see it better.

 

No. I don't think so. The screen brightness goes down so you would not get blinded by the screen. Same with the keyboard.

It finds what the light is and then adjusts all of its components to optimize for that lighting condition.

Everything seems to be working fin.

 

It is working as designed.