Unclear modeling of subPropertyOf

[nichtich]

Modeling with subPropertyOf is unclear.

The ontology states for instance:

:hasBearsDate rdf:type owl:ObjectProperty ;
              rdfs:subPropertyOf :hasAppearance ;

The documentation exemplifies (link to archive bc nomisma.org is down):

:Coin_1 nmo:hasApperance [ nmo:hasBearsDate "0231"^^<xsd:gYear> ] .

So with RDF inference the data would be expanded to:

:Coin_1 nmo:hasApperance [
  nmo:hasBearsDate "0231"^^<xsd:gYear> ;
  nmo:hasApperance "0231"^^<xsd:gYear>
] .

Is this intended? Reading the ontology I'd assume the example is wrong and it should instead be

:Coin_1 nmo:hasBearsDate "0231"^^<xsd:gYear> .

expanding to

:Coin_1 nmo:hasApperance "0231"^^<xsd:gYear> .
:Coin_1 nmo:hasBearsDate "0231"^^<xsd:gYear> .

I guess either the ontology statement is wrong (don't use subPropertyOf) or the example is wrong (don't use intermediate blank nodes).