Order &1 does not belong to master order &2

What causes this issue?

The specified order number does not belong to the master order when you
are unassigning planned order or production order from the master order.

System Response

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

How to fix this error?

The order number that needs to be unassigned from the master order
should belong to the same master order.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.