Combination of material provision indicators for forw. exch. inconsistent

What causes this issue?

Maintenance order:
If a material provision indicator (MPI) for forward exchange (deferred
delivery) is used, then exactly 1 component with an MPI that is
customized as 'A&D-specific' and 'provided by vendor' has to be
added.
Example: if there is 1 (or more) material provision indicators 'F'
<ZK>(Deferred Delivery)</>, then there has to be exactly 1 with 'X'
<ZK>(Rework Material from Subcontractor)</>. No other material provision
indicator is allowed.
Purchasing:
It is not allowed to mix components with deferred delivery and other
material provision indicators. That means that all components must have
the <ZK>Deferred Delivery</> indicator or none.

System Response

The system stops processing.

How to fix this error?

Correct the material provision indicators as described.

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.