A donor already exists in the Participant Center Address Book for a participant, yet every time they donate, a new contact entry is added to the list.
The Address Book in the Participant Center matches to existing records using email address criteria. However, no merges or de-duplication are performed because the Luminate Online system, Blackbaud administrators, and your organization administrators do not have permission from the participant to adjust records in their address book. The state of a participant's address book is entirely up to them. They can group contacts, add new emails, or delete records as they see fit.