Relationship between object & and its predecessor & may be n:m

What causes this issue?

The object &V1& and its predecessor object &V2& may have an n:m
relationship, as not all key fields of &V2& are in the field
dependence.

System Response

The View cluster is nevertheless activated.

How to fix this error?

Check whether you have completely specified the relationship between
object &V1& and its predecessor &V2& in the field dependency, and add
any missing dependencies.
If the relationship is complete, &V1& and &V2& have an n:m
relationship. If this is the case, you must set the field "n:m" in the
associated entry in the viewcluster object structure.

Error message extract from SAP system. Copyright SAP SE.