SAP Message CB519 - Reservation item for material & is not unique

Diagnosis
With the selected process message, material consumption data istransferred to destination &V2&. However, the message does notcontain the corresponding reservation number and item. For thisreason, the material consumption cannot be uniquely assigned to areservation item.

System Response
The material consumption is posted to the first reservation item forthe material for which the final delivery has not yet been made.