Facebook recently made a significant change on their platform. all the users were automatically assigned @facebook.com email addresses and these were made the default email address on all user profiles.
This caused a major problem for smartphone users who were syncing their Facebook account with their address book.
For some users, this syncing process replaced email addresses of all Facebook contacts with the @facebook.com id.
As a result, emails sent through the mobile device were landing on Facebook instead of the user’s preferred email address.
Facebook has stated that this was caused due to a bug in the sync API and it is currently being fixed.
The company said:
Contact synchronization on devices is performed through an API. For most devices, we’ve verified that the API is working correctly and pulling the primary email address associated with the users’ Facebook account. However, 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, resulting in @facebook.com addresses being pulled. We are in the process of fixing this issue and it will be resolved soon. After that, those specific devices should pull the correct addresses.