3816553 - Why 720 employee import job run status showing Success while Authorized Approver not updated as expected?

We use 720 employee import file to add new Authorized Approver and job run status showing "Success". However, we found some approvers not created as we expected. For example, we want set one approver at one hierarchy level with 2 approval levels, while in system we could see this approver has Only one approval level. May I know why this happened?

720 employee import job run status showing Success while Authorized Approver not updated as expected , KBA , CON-EXP-ADM-WFL-WL , Workflow , CON-CA-TLS-IEM , Import / Extract Monitor , Problem