Typically, Facebook users can customize which emails or text notifications they receive, whether it's for friend requests or new Facebook events. But on Tuesday, users began complaining that their selected email notifications had been reversed. For instance, those who had opted not to receive emails for events, were suddenly receiving emails about them, while those who'd checkmarked that box were not receiving emails at all.
This prompted Facebook to post the problem on its "Known Issues on Facebook" page on Tuesday night: "Some people are suddenly receiving email notifications for settings they had turned off, and the checkboxes are now checked. We are currently working on a solution to this problem.
By Wednesday afternoon, Facebook apologized and declared the problem resolved.
"Yesterday evening, we discovered a bug that caused a small number of people to start receiving notifications they had previously turned off. We have since resolved the issue and apologize for any inconvenience," a spokesperson said.
Last Friday some Facebook users also reported seeing an error message when trying to access their "Notifications" menu, which Facebook said it resolved within 24 hours.
On Monday, U.K.-based security company Sophos published an open letter to Facebook on its blog, Naked Security, urging Facebook to improve its opt-in privacy schemes, vet app developers (where many phishing scams originate), and turn on a secure connection (HTTPS) standard.