The social network has confirmed that a bug in its notification system meant that it sent out many more push notifications, emails etc. than it should have, reported The Guardian.

Typically, Facebook only sends one notification per birthday to users, and only sends emails to those who have chosen to receive the notification through mail.

But over the past month, some users have reported a massive increase in notifications from the website, giving multiple prods over multiple media to wish friends a happy birthday.

While many assumed the change was deliberate, or perhaps a form of user experience testing, it was apparently a freak accident.

Facebook confirmed that the bug, which has now been fixed, resulted in users, who had never signed up to email notifications for birthdays, being sent the notifications.