Metadata language after import (and before edit) not as expected

[heidivanparys]

I created the following small test file.

<?xml version="1.0" encoding="UTF-8"?>
<rdf:RDF
    xmlns:foaf="http://xmlns.com/foaf/0.1/"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:dcat="http://www.w3.org/ns/dcat#"
    xmlns:dct="http://purl.org/dc/terms/"
    xmlns:skos="http://www.w3.org/2004/02/skos/core#"
    xmlns:vcard="http://www.w3.org/2006/vcard/ns#"
    xmlns:dcatap="http://data.europa.eu/r5r/">
    <dcat:Catalog>
        <dcat:dataset>
            <dcat:Dataset>
                <dct:description xml:lang="en">Description</dct:description>
                <dct:description xml:lang="nl">Beschrijving</dct:description>
                <dct:identifier>cec47785-bfbc-416a-8c85-7648b6c07abc</dct:identifier>
                <dct:publisher>
                    <foaf:Agent>
                        <foaf:name xml:lang="en">Example organisation</foaf:name>
                        <foaf:name xml:lang="nl">Voorbeeldorganisatie</foaf:name>
                        <foaf:mbox rdf:resource="mailto:example@example.org" />
                    </foaf:Agent>
                </dct:publisher>
                <dct:title xml:lang="en">Minimal example with English and Dutch</dct:title>
                <dct:title xml:lang="nl">Minimaal voorbeeld met Engels en Nederlands</dct:title>
            </dcat:Dataset>
        </dcat:dataset>
        <dcat:record>
            <dcat:CatalogRecord>
                <dct:language>
                    <skos:Concept rdf:about="http://publications.europa.eu/resource/authority/language/ENG">
                        <skos:inScheme rdf:resource="http://publications.europa.eu/resource/authority/language" />
                    </skos:Concept>
                </dct:language>
                <dct:language>
                    <skos:Concept rdf:about="http://publications.europa.eu/resource/authority/language/NLD">
                        <skos:inScheme rdf:resource="http://publications.europa.eu/resource/authority/language" />
                    </skos:Concept>
                </dct:language>
                <dct:identifier>b5d89334-2424-4751-a23b-cb994c4825e7</dct:identifier>
            </dcat:CatalogRecord>
        </dcat:record>
    </dcat:Catalog>
</rdf:RDF>

When I import and view the record, "en" is listed as a Metadata language (together with "English" and "Nederlands", independent of whether I choose Dutch or English in the GUI.

When I edit and save the metadata record (after applying the commit mentioned in #134), the display is as expected, "en" is not listed any more as Metadata language:

This issue is relevant when harvesting DCAT-AP metadata records from other data portals, and metadata is shown as is.