Description: This solution discusses why a record that is already in Mailchimp may end up in the New bucket when sending records to Mailchimp
Environment: All
Versions: All
Answer:
That contact can no longer be used as a match via the API because it previously bounced and is now in a "cleaned" status.
You can read more about cleaned contacts in Mailchimp here.
If the record was attempted to be sent over from the New bucket it would land in a Destination Exceptions bucket with an error stating that it has a status of "cleaned" and cannot be updated via the API.