If the conversation is sent from the admin, it is expected that it would be marked as read (since it's from yourself). The issues is when explicitly adding other admins/mods as recipients, in which case they don't get the notification. I would suggest adding notifications for additional recipients so admin 2 can reply to the conversation from admin 1 to member, with a welcome message as well. If they don't want notifications of these conversations, they you can just remove them as additional recipients.