I usually play PUBG in outdoor condition, with no problem at all. What I have noticed is that if I switch between windows this is very noticeable, or on certain pages it will go to bright, then everywhere else it will be dim again. Head to Settings > Accessibility > Display & Text Size. Meaning I got 100% brightness in the system, but with a low brightness. The brightness setting doesnt change, but the screen just seems to fade in and out as if the brightness is changing. So if your iPhone screen dims on its own, the auto-brightness feature could the culprit. But when you check the manual setup brightness, brightness is at maximum. To explain the problem: It's like the ipad believes that my system is running hot, so it decides automatically to reduce the brightness (like the OS is trying to reduce the energy used or something like that). Like I lost let's say more or less 25/30% of the max brightness. I did a reboot, I deactivated the auto brightness, still, the problem remains. Or, Every computer has Power Options or bas. If your In-Game Settings have been set to Lower brightness level or Lower Gama than your normal screen brighness, then it might be decreasing your brightness when you start your game 2. The brightness has been significantly reduce for no reason, and it annoys me a lot as i'm using it a lot outside. Answer (1 of 2): There are 2 possible Answers to this questions 1. I agree with a previous poster there is a glitch somewhere, and/or someone at Apple screwed up!I got the same problem with my ipad pro since some days. My screen dims randomly, and returns to brightness just as randomly.

My brightness is all the way up, auto brightness and low power mode is off.

I have an XS Max, as well as an iPad Pro, and I have the same issue with both devices.

Screen dims and brightens randomly