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.
A Facebook official said the social network did intend to give its new @facebook.com e-mail addresses exclusive visibility on user profiles, but insists that a software bug is responsible for resetting your contacts' e-mail addresses the same way.
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, Facebook engineering director Andrew Bosworth told the Verge. This meant phones were pulling down @facebook.com addresses, unknown to their users -- resulting in messages sent to the wrong, and often unchecked, inboxes.
A Facebook spokesperson told CNET that most devices did not have the issue, but the company is still working on fixing the issue for some devices.
"We are in the process of fixing this issue and it will be resolved soon," the spokesperson said in an e-mail. "After that, those specific devices should pull the correct addresses."
Until then, users can still adjust their privacy settings to get their show their primary e-mail address and not their Facebook one.
The company intended to give users more control over their messages through the new e-mail system, according to the spokesperson.
In account settings, people can specify whether they want to receive messages from Friends, Friend of Friends, or Everyone. If someone sends an e-mail to your @facebook.com address and it's from an address associated with a Facebook friend or friend of friend's accounts, it will go into the inbox. If it's from an address not associated with a friend or friend of friend's Facebook account, it will go into your other folder. If you've specified in privacy settings that you only want to receive messages from friends or friend of friends, then the message will bounce.
"We've noticed that in a very limited number of cases, the bounce e-mail back to the original sender may not be delivered because it may get intercepted by spam filters," the spokesperson said. "We are working to make sure that e-mail senders consistently receive bounce messages."