2821735 - During an OData Service redefinition "Mapping not allowed. The model <ModelName> in project is redefining another model.> error message is coming

Redefining an OData service (Data Model -> Redefine -> OData Service (SAP GW)), then adding a new Entity Type/ Set and mapping a data source to it (Service Implementation -> right click on the given Entity Set -> Map to Data Source) fails with error message:

"Mapping not allowed. The model <ModelName> in project is redefining another model.>

SAP Gateway (SAP_GWFND)

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