[OnePlus 5T  Guides, News, & Discussion] Funk Wizard:
Some FAQ's on Android Pie Release

Q. Why is my brightness low after upgrading to Android Pie 9.0?

A: Google introduced new algorithm for the brightness which will give more control to the user specially in darker environments. The user have to train the brightness preferences for some time in different lighting conditions they use their device so that the device learns it and then adjusts the brightness automatically after that.

More here: https://forums.oneplus.com/threads/behind-the-scenes-how-we-adapted-to-android-pie.909531/

Q. Where is clear Cache in Android Pie?

A: Cache partition no longer is available on Pie. So there is no option for clearing it. One has to clear cache by individual app now.

https://www.howtogeek.com/356365/why-android-no-longer-needs-a-cache-partition/

Cache's Explained Here:

https://forums.oneplus.com/threads/caches-explained.828298/

Q. Why is there no Digital Well-Being available in OnePlus device running Pie?

A: Digital Wellbeing is currently available only to Pixel devices and Nokia 7 Plus. This may change in near future and OnePlus may be added to its supported device list.

Q.Why is "X" app crashing in my phone running Android Pie?

A: Many apps are still not updated to support Android Pie, that is the reason they are not able to run in the new OS. Contacting the app developer will be much more helpful.

Q. I downgraded to stable channel, but did not receive the update to Pie, why?

A: The wide-rollout has begun, its only matter of time, you will get the notification for the new update.

Q. Why is my battery draining so fast after update?

A: This is a major upgrade, you should give it some time to settle before the battery starts working normally. Also battery calibration is always a good way to get most out of it.

Q. I do not like the new Recents layout, what can i do?

A: Unfortunately, nothing can be done about it. Its how Google designed it.

Q. I cannot activate the new Pill gestures, why?

A: Sometimes update messes up app data and settings. To solve this clear OnePlus Launcher data and reboot the device.

Q. My Play Store is showing "uncertified" after i downgraded to stable, how can i solve it?

A: Clear Google Play Services data and Play store data and Reboot. Let Play store update automatically and it should change the status to Certified.

Q. Why cannot i use volume buttons to control the ringtone volume in Android Pie?

A. Google has made change to it, now we can change media volume by default. OnePlus has provided a shortcut to directly go into settings to make it easier to change the ringtone volume.

Q. Why my Fingerprint does not work, after my phone is in standby for long time?

A: The Fingerprint service goes to sleep and thus doesn't allow unlocking the phone.

To avoid this, the current work-around it to turn Off Standby Optimization in Advanced Optimization Battery Settings or wake up the phone using Power button after long standby.

Q. Why does not my screen light-up on incoming calls?

A: This happens when the Phone app settings is messed up.

To solve this:

Touch and hold on Phone app and Tap on App Info.

Now tap on Notifications and then tap on Incoming Calls(Not the Checkbox).

Select Behavior and make sure its set to Make Sound and Popup on Screen

This should allow the incoming calls to notify you lighting up the screen.

Q. My clock shows alarm notification 2-hrs prior to actual alarm/ my alarm is missing, what can i do?

A: You can follow the steps below to fix it:

Go to Settings>Apps & notifications>Display all apps>Clock>Notifications.

Now, there are 2 things to do :

a) Press on "Clock" (Not the Checkbox)>Behaviour

Choose "Silent display" : this way you won't have the sound notification 2 hours before schedule

b) Press on "Alarm" (Not the Checkbox)>Behaviour

Choose "Sound alert and display on screen" : If you choose another option, the screen won't turn on when the alarm rings. And you also want to set the sound alert to none. Otherwise, when the alarm rings, you'll also hear the notification sound.

Q. Why is my slow-mo videos stuttering?

A: It seems to be a known bug currently. Developers are aware of the bug and are working on it. The fix could be released in future update.

Please go through this Q&A before making any bug reports and attach the logs with the reports.

Thank you :good:

Q&A Source