When guests sign up using the Facebook SSO, if they do not give permission to access their email, then a random generated email is sent to Punchh similar to 123456789101112@fb.punchh.com. If guests later provide access to the email, it will be stored as the secondary email but the randomly generated email will remain and will not update since Facebook is no longer sending us webhooks with the updated information for this email but the secondary email will get updated.
If further assistance is required, submit a ticket to Punchh Support. (For help submitting a ticket, click here)