You have a transaction in the NetCommunity plugin from a constituent linked in the database. The constituent has profile updates that include their Address and a phone or email address. When processing the Profile Updates, you choose to reject the address information and choose to add the phone or email to the record. After saving the profile changes, the phone or email address is added as expected, however a duplicate address is also added to the record.
This issue was resolved in the latest version of Blackbaud NetCommunity.