Facebook has admitted its mobile app altered phones' contacts books to use @facebook.com addresses.
The hijack stems from a flaw in the website's design and the decision to provide every user with an @facebook.com handle that forwards to their Facebook message inbox. These addresses are now shown on the site's Timeline to encourage their use.
A bug in the Facebook contacts API caused the mobile client to download and save the most recently added email address, rather than the account default, when synchronising a user's friends list and the phone's contact book. Because the "most recent" was the Facebook address, punters' contacts were rewritten and their email rerouted as a result.
Reports of missing messages were, as predicted, down to mails from non-friends being filed away in the "Other" mailbox on the social network. That's a feature which must surely annoy anyone using Facebook groups (messages from other group members get similarly tucked away) but it's really a result of one not having enough mates.
Despite overwriting personal address books and hiding received emails, Facebook is anything but contrite. The official statement from the company explains that "for people on certain devices, a bug meant that the device was pulling the last email address added to the account rather than the primary email address" without any obvious admission of whose bug that was.
It was Facebook's bug.
Team Zuck says it will have a fix in place first thing on Thursday, after which contact lists will automatically return to using the default email address - assuming the affected users still have the Facebook app installed and set up to synchronise. ®