Why is my phone screen dimming while reading with auto-brightness off?

[Aubrey93]

My new phone’s screen keeps going dim while I’m reading an article, even though I have the auto-brightness setting turned off. It’s especially annoying in a moderately lit room, and I have to keep tapping the screen to brighten it back up.

[Robert.C]

Yep, same thing here. auto brightness off but in a dim room the screen would dip to a dull level. I noticed it when the battery saver kicked in turning that off mostly fixed it but not always.

[Matthew35]

I suspect adaptive brightness or a per app brightness override. After a system update mine started dimming in articles until I disabled adaptive brightness.

[Zoey61]

I kept tapping to brighten, felt like a tiny ritual. I read a few paragraphs then paused just to rub my eyes and keep going.

[BrianYW]

Could be sensor blocked by case or screen protector or something else in the way. Did you check if the ambient light sensor is blocked by a case or screen protector?