3495538 - Error M3071 "Enter the lot size (materials planning)" when using Product Master (A2X) API

Error M3/071 "Enter the lot size (materials planning)" occurs when using POST or PATCH method for a product in the API_PRODUCT_SRV, even if the fields "MRPResponsible" and "LotSizingProcedure" from "to_PlantMRPArea" are correctly filled.

SAP S/4HANA Cloud Public Edition

1. Setup a payload for the product with "MRPResponsible" and "LotSizingProcedure" fields from "to_PlantMRPArea" node correctly filled. 
2. Send POST request to the Product Master (A2X) API with the payload
3. The API returns error M3/071 "Enter the lot size (materials planning)"

This is the standard system behavior controlled by the MRP procedure defined in the MRP type.

• For MRP types (MARC-DISMM field) defined with MRP procedures N (No MRP) and W (Retail), the MRP controller and Lot Sizing Procedure are optional.
• For MRP types (MARC-DISMM field) defined with other MRP procedures, the MRP controller and Lot Sizing Procedure are mandatory.

The relevant MRP controller or Lot Sizing Procedure for the product based on the MRP type is missing in the payload.

The LotSizingProcedure can be found in both the "to_PlantMRPArea" and "A_ProductSupplyPlanning" nodes. (Schema View | Product Master (A2X) | SAP Business Accelerator Hub) 

Ensure that the payload includes the relevant node "A_ProductSupplyPlanning" with the MRP Controller ("MRPResponsible") and Lot Sizing Procedure ("LotSizingProcedure") fields properly filled.

• KBA 928466 - Handling of fields present in multiple nodes
• Enter a valid lot size (materials planning) error | SAP Community Q&A
• API_PRODUCT_SRV - Supply_Planning_Data | SAP Business Accelerator Hub
• Supply Planning Data | SAP Help Portal

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