HDL Change Assignment Error

Summary:

Hello,

I am getting the same error "WorkTermsNo assignment record exists from 2019-12-04." I am not sure what is wrong?!

Any assistance is GREATLY appreciated!

Here is the code:

METADATA|Worker|SourceSystemOwner|SourceSystemId|PersonNumber|EffectiveStartDate|ActionCode|DateOfBirth|StartDate|EffectiveEndDate

MERGE|Worker|ABC|W100019591|1001637|2019/09/23|HIRE|1980/08/20|2019/09/23|4712/12/31

METADATA|PersonName|SourceSystemId|SourceSystemOwner|NameType|PersonNumber|EffectiveEndDate|EffectiveStartDate|FirstName|LastName|LegislationCode|MiddleNames

MERGE|PersonName|PN100019591|ABC|GLOBAL|1001637||2019/09/23|Paul|Small|US|

METADATA|WorkRelationship|SourceSystemId|SourceSystemOwner|LegalEmployerName|PersonNumber|DateStart|WorkerType|ActionCode|OnMilitaryServiceFlag|PrimaryFlag|RehireRecommendationFlag

MERGE|WorkRelationship|WR100019591|ABC|COMPANY|1001637|2019/09/23|E|HIRE|N|Y|N

METADATA|WorkTerms|AssignmentNumber|PeriodOfServiceId(SourceSystemId)|LegalEmployerName|PersonNumber|DateStart|WorkerType|EffectiveEndDate|EffectiveLatestChange|EffectiveSequence|EffectiveStartDate|ActionCode|AssignmentStatusTypeCode|AssignmentType|BusinessUnitShortCode|DefaultExpenseAccount|ExpenseCheckSendToAddress|DepartmentName|GradeCode|LabourUnionMemberFlag|LocationCode|ManagerFlag|PositionOverrideFlag|PersonTypeCode|PositionCode|PrimaryWorkTermsFlag|PermanentTemporary|UnionName|SourceSystemId|SourceSystemOwner