Start with Sample2b, and then open the admin UI https://localhost:8443/admin. Be sure there are records within your OpenDJ server. Trigger recon for your systemLdapAccounts_managedUser mapping - you will see the records for both the source and target within the Data Association Management grid, under the correlation tab. Note the first record that is listed there.
Now go to OpenDJ's control panel and delete the record which you noted as the first one shown in the grid.
Go back to the Admin UI and refresh the page that has the correlation data grid. Now instead of seeing just one missing record, you will see that every record in the grid is showing as "not found" on the LDAP side.