Unfollowing, then refollowing will not generate a notification.
Our system prohibits notifications in this case, so it’s normal that you won’t receive a notification.
Why block the notifications? To prevent trolls, spam of unfollows and refollows.
Please note that this applies to unfollows and refollows that occur within a defined period of time. Refollows that occur after more than 24/48 hours will be displayed without being blocked (if you have activated the option).