Facebook said a bug can reset your contacts’ e-mail addresses to its new and largely unwelcome @facebook.com mailbox — overwriting the original address info in the process.

The social network’s faux paux that outraged Facebook users and prompted misdirected e-mails throughout the Web was actually caused by a bug, FB said.

On certain devices, the bug was syncing the last e-mail linked to the account instead of the primary address set by a user, according to Facebook engineering director Andrew Bosworth.

This meant phones were pulling down @facebook.com addresses, unknown to their users — resulting in messages sent to the wrong, and often unchecked, inboxes.

Source: CNET News