Xs Max brightness Bug

I found a bug with Xs Max. If I manually set the date to 1 day later and then set it back to Auto, the brightness level will be forced to lowest level and cannot be adjust any more by scrolling the brightness bar. The solution is set the time back to 1 day after, or wait about 20-30 seconds, the brightness will come back to normal BY ITSELF.

The reason I found this bug is, I am a candy crush player, I use this trick to cheat the game life limit.