I can take some logical guesses, but I don’t really know either.
AutoRestore|Quarantine backs up files when you run the Setup Wizard. If a file changes, the backup file in AutoRestore backup is used to restore the file with that backup file. So if the robots.txt file in AutoRestore backup was the second one that you posted and you edited your existing robots.txt file with the new code that you posted above then AutoRestore would restore the second robots.txt file that you posted above.