HDL to update supervisor is failing with error "corresponding date effective record...is missing..."

Summary:

Using pattern from https://docs.oracle.com/en/cloud/saas/human-resources/22a/fahbo/how-you-update-line-manager-for-an-employee.html#s20081757 we populated Worker.dat file

But during execution getting error: "The corresponding date effective record in the {PARENTNAME} for date {DATE}, action {ACTION}, and effective sequence {SEQ} is missing for the {CHILDNAME}."

checked halfdozen times each record to be consistent with sample shared in above url

i guess i'm not understanding correctly how these 3 records: WorkTerms, Assignment, and Assignment supervisor link each to other.

am i referring to existing Workterms, Assignment, and creating new dates for Supervisor assignment or all 3 records should carry new dates for supervisor change?