E: Subfeature & does not exist yet

What causes this issue?

A feature that accesses a subfeature can only be saved or generated if
the subfeature exists and has been checked and saved.

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?

If the subfeature in question is located in your decision tree, choose
it. Executing this function takes you back to the feature maintenance
screen, which enables you to create and save the subfeature. If you
choose Back, you go back to the feature maintenance screen for the
initial feature.
Note: You can choose the Save without check function at any time.

Error message extract from SAP system. Copyright SAP SE.