The first option, System Preferences → iCloud → Mail, controls whether the iCloud Mail account is available in the Mail app. Unchecking this option will remove the account from Mail, along with all the associated email. This won’t permanently delete the mail: it will still be accessible on iCloud.com, and in Mail if you switch the option back on.
To control some settings of Apple Books on your iOS device, you need to have iCloud Drive turned on: Go to Settings > [your name] > iCloud and turn on both iCloud Drive and Books. Then go to Settings > Books.
Under Syncing, you can change settings like these:
Turn on Reading Now to sync your reading progress, current book, notes, and bookmarks using your ...
That is normal and documented by Apple. (yes it is a known bug, but you didn't lost anything. They were all moved to your iCloud under Documents and/or Desktop folders.
You have to download them from iCloud again
If you want to change settings:
Change this setting under System Preferences -> iCloud (save "Documents and Desktop" on iCloud.
but this "...
So the issue was the following:
iTunes Backup changes to "iCloud" when "This Computer" is selected when iPhone is connected to iTunes.
when connecting to iTunes in iPhone(YourIphone) > Summary > Backups the "iCloud" option was checked. When I had set the "This computer" option. So when I set it again to "This computer" option and clicked ...