Higher-level and predecessor nodes: Deviating values of entity type &1

What causes this issue?

You can only process higher-level nodes and predecessor nodes in
individual processing if the higher-level entity types are restricted to
the same value for all affected nodes (both nodes to be assigned and
existing nodes).

System Response

The higher-level nodes and predecessor nodes cannot be changed in
individual processing.

How to fix this error?

Use hierarchy processing to process the higher-level nodes and
predecessor nodes.

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.