Lexmatch: inconsistent behaviour in `sqlite` and `default` mode

[matentzn]

According to documentation, I should be able to use lexmatch with other ontology interfaces. However, while this here works fine:

runoak -i sqlite:foodon_wd.owl lexmatch -o foodon_wd_lexmatch.tsv

This here:

runoak -i foodon_wd.owl lexmatch -o foodon_wd_lexmatch.tsv

results in an empty mapping set data frame (with curie map and all, just no mappings).

The following warnings are printed:

WARNING:root:Using rdflib rdf/xml parser; this behavior may change in future
WARNING:root:Not a curie: foodon.owl
WARNING:root:Not a curie: foodon.owl

One idiosyncrasy of the ontology in question is that contains entities with no OWL typing in it:

<rdf:Description rdf:about="http://www.wikidata.org/entity/Q10374646">
        <rdfs:label>cashew apple juice</rdfs:label>
    </rdf:Description>