Nested namespace registration for prefix &1

What causes this issue?

Handler classes registered namespaces that are nested within each other
when registering:
Class &V2&, namespace &V1&
Class &V4&, namespace &V3&
This is not permitted, since it means that it is no longer possible to
uniquely assign entries to a handler.

System Response

Both of the above handler classes are ignored in the further processing
of the program.

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

There is a programming error in the handler classes.

Error message extract from SAP system. Copyright SAP SE.