$mailingGroup = new CRM_Mailing_DAO_MailingGroup();
$recipientsGroup = $excludeSmartGroupIDs = $includeSmartGroupIDs = $priorMailingIDs = [];
$dao = CRM_Utils_SQL_Select::from('civicrm_mailing_group')
- ->select('GROUP_CONCAT(entity_id SEPARATOR ",") as group_ids, group_type, entity_table')
+ ->select('GROUP_CONCAT(DISTINCT entity_id SEPARATOR ",") as group_ids, group_type, entity_table')
->where('mailing_id = #mailing_id AND entity_table RLIKE "^civicrm_(group.*|mailing)$" ')
->groupBy(['group_type', 'entity_table'])
->param('!groupTableName', CRM_Contact_BAO_Group::getTableName())