Changing variables of attribute normalizing rule assigned incorrectly

What causes this issue?

All interface variables of an attribute normalizing rule of type
"Changing" must be assigned to the same node of the data model. This is
not the case for attribute normalizing rule &V1& (call number &V2&).

System Response

The object normalizing strategy is inconsistent and cannot be executed.

How to fix this error?

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

Procedure for System Administrators

Correct the object normalizing strategy.

Error message extract from SAP system. Copyright SAP SE.