Thank you for reaching out to the Community! I apologize for any confusion that this has caused, but when sending test emails from your account to yourself or to your colleagues the Greeting Tag will always populate with the Account Owner's name. When you send a live version to your contacts the Greeting Tag will be able to pull their information instead of yours.
I'm having the same issue now. Caused me quite a bit of stress! Confusing to me why the "test" wouldn't be an accurate representation of what will actually happen. 3 years later and this issue still isn't fixed? common now!
Since test emails can be sent to non-contacts, we are not able to pull contact info through the test email system besides the account owner's. If you want to "test" the email with contacts, then we recommend setting up a separate test list of contacts and sending the "test" as a live email to that list.