Fusion ERP Cloud - findEntity in Custom object API not working properly

I am using the following SOAP API: /crmService/CustomReferenceService Method: findEntity

I am trying to search based on 2 filter criteria, one with parent Custom object and another with Child Custom object. but it is returning results of all parent Custom Object only:

in the below Payload: SQMSiteDetailsHub_c is the parent custom object which has child custom object as: PSApprovals_c. but it is working fine on parent filter criteria. but it is not narrowing down based on childFindCriteria. please help

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:typ="http://xmlns.oracle.com/apps/custom/extnService/types/"