Apple logo with progress bar screen keeps popping up after update
I upgraded my iPad (3 gen, wifi) from iOS 5.1 to 8.3 and restored it from the backup two days ago. And since then a progress bar screen with apple logo (as same as the screen when restoring) frequently pops up.
At first I thought it was syncing the stuff from icloud, but later I found that it just happen too much.
Here are the pattern I found about the progress bar screen:
1. it pops up EVERYTIME when (i)unlocking the screen, (ii)switching app store account, (iii)entering the icloud setting page
2. it pops up sometimes when opening applications
3. the progress bar takes about 20-30 seconds to finish, but usually it will repeat for 2-3 more times taking total 1-2 minutes each time it happen.
4. it happens regardless the device is connected to internet or not
iPad (3rd gen) Wi-Fi, iOS 8.3