For some reasons, iCloud Drive keeps the old data doesn’t let your device to save new data.
To fix this issue, Please follow these instructions below:
1. On your iPad, go to Settings => Search for “iCloud Drive” => Turn off iCloud Drive (Temporary, turn off iCloud Drive feature of the device).
2. Go back to the Home Screen => Launch Wings Of Duty => Go to Pilot Profiles => Tap on RestoreAccount button.
3. Go back to Settings => Turn on iCloud Driver again.
After these steps, the game should be able to save its data as before.