SAP Message V50R056 - Several items from the same system have the same CUOBJ_CH

Diagnosis
When generating deliveries for preceding documents from an externalsystem, an error occurred whereby several items from the same systemwere assigned the same internal key for characteristics and valuationsfor batch determination.
For batch classification, this represents an inconsistency.
The source of the error can only be removed if the program that fillsthe BAPI interface ensures that each preceding document item receivesits own key for the batch characteristics.