3797390 - MRP Planning result is not as expected when Co-Products are involved in a recursive BOM structure

When executing Material Requirements Planning (MRP) for materials that are defined as co-products in a recursive BOM structure, the planning results are not as expected.

Observed behaviors may include, but are not limited to:

• Redundant planned orders or purchase requisitions are generated.
• The final available quantity does not equal zero after planning.
• Running MRP repeatedly yields different, inconsistent results.

SAP S/4HANA Cloud Public Edition

1. In plant e.g. 1010 , define materials A, B, and C as co-products.
2. Maintain the BOM structure as follows, creating a recursive dependency:
   Material A → Components: B (co-product), C (co-product)
   Material B → Components: A (co-product), C (co-product)
   Material C → Components: A (co-product), B (co-product)
3. Execute MRP for plant 1010 via the Schedule MRP Runs app or equivalent.
4. Navigate to Monitor Stock / Requirements List or Manage Material Coverage.
5. Observe that the planning results are inconsistent or not as expected (e.g. redundant proposals, non-zero final available quantity etc.).

The root cause of this behavior is a recursive BOM structure, which is not supported in SAP standard MRP — regardless of whether the recursive indicator is explicitly set.

In a standard MRP run, BOM components are assigned low-level codes that determine the sequence in which materials are planned. Components at lower BOM levels are always planned after their parent assemblies, ensuring that demand from higher levels is fully considered before lower-level planning begins.

However, when co-products are configured in a mutually dependent BOM structure as described above, this creates a situation where materials A, B, and C are effectively at the same BOM level, introducing circular dependencies. In such cases, the low-level code logic breaks down, and MRP can no longer guarantee that planning results at one level are fully considered before planning the next.

This is not a defect in MRP. It is a system design constraint related to recursive BOM structures. The same behavior would occur even without the use of co-products, if a recursive BOM dependency exists between materials.

The recursive BOM configuration is not supported in SAP standard MRP.
Review and redesign the BOM structure to avoid circular dependencies.
For instance :
1. Refine the co-product setup to have a leading material with normal MRP type PD, where all the original demands are placed. 
    Maintain the other co-products as dependent materials with MRP type ND.
2.Maintain all co-products as one material number.

Where redesign is not possible, performing manual corrections.

Co-product, co product, Recursive BOM,low-level code, MRP , KBA , PP-MRP-2CL , Material Requirements Planning (Public Cloud) , Problem