Error occured during low-level code assignment

What causes this issue?

An error has occred when setting and checking the low-level code.

System Response

This same low-level code is used in the master data for all materials
of a supersession chain or an FFF-class, so that the materials in the
MRP run can be planned together. The system then checks the low-level
codes of all interchangeable materials. This is where an error
occurred.

How to fix this error?

Check the BOM usage for all materials of the chain or the class.
Maintain the material interchangeability (the supersession chain or the
FFF-class) again.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.