Primary/Secondary Sender Name Error
When your Secondary Mailbox was created, a Contact was automatically added to your directory called Partner.
Please delete the contacts with you and your Secondary's names on them.
Instead, use the contact called Partner to send each other messages.
It is the two contacts with your names on them that are causing the error in sender display when you and your Secondary are sending each other messages.
Please note that this applies only to messages you and your Secondary send to each other. Messages you send to your Upline will have your names on them.