What causes this issue?

For the current compliance requirement, you chose a normalization
variant (&V2&) that is not configured as default variant for being
displayed in the compliance workbench. Your activity can result in a
view with an incomplete product structure tree.

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?

Choose another normalization variant or configure the chosen
normalization variant as default in the <LS>Specify Compliance Views and
Normalizations</> Customizing activity under <LS>Product Compliance for
Discrete Industries -> General Configuration -> Compliance Object.</>

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.