Unable to Terminate Contingent Worker through HDL

Summary:

We are unable to terminate contingent worker loaded from third party system through HDL.

Content (required):

We have a requirements to synchronise contractors maintained in our third party system into Cloud HCM. When we trying the terminate the contingent worker using HDL, we are getting "The WorkTermsSDO attribute value is required. You must enter a value." error even after setting TerminateWorkRelationshipFlag to Y. Since the data is coming from third party, we are unable to provide person_id or person_number, hence we have to rely on SourceSystemIds. Below are the HDL snnippet.

Kindly provide a guidance to resolve this issue.