Android’s 4.2 Update Filled With Bugs
This bug isn’t one I’ve experienced personally, but many, many others -including Artem – have. After the Android 4.2 update (or just on the Nexus 10, in general), auto-brightness behavior has been less than reliable, particularly on the Nexus 7 – though that device’s problems aren’t strictly limited to Android 4.2.
The issue specific to the Nexus 7 causes the screen to noticeably flicker when set to auto-brightness, and has been present on all Android builds, especially at low levels. With the Android 4.2 update, that behavior has apparently gotten worse. Yikes. Which leads us to the generic auto-brightness bug.
Auto-brightness in Android 4.2 seems to randomly adjust with no changes in ambient lighting, as though the sensitivity is too high, or some sort of other software glitch is causing the brightness setting to suddenly drop, then come back up to the appropriate level. Basically, auto-brightness is borked. While I never found auto-brightness on the Nexus 7 was good in the first place, many are now complaining it is much worse, and on the Nexus 10, as well. Did You upgrade??