Facebook has been dealing with a number of privacy issues surrounding its platform including the Cambridge Analytica scandal and a bug that changed 14 million users' privacy setting defaults to public. Unblocking blocked accounts without a users' consent is a major blunder on Facebook's part and one that could have caused some users harm.

Facebook says it's notifying anyone who was affected by the unblocking error. The bug is now fixed and anyone who was unblocked has been blocked again.