Adding and removing modified times leaves detritus

[luciansmith]

Because of Reasons, I'm adding modified dates to a model, then replacing it with a new modified date. So inbetween, I call 'unsetModifiedDates'. This mostly works, but I end up with a bunch of empty RDF 'Description' objects:

        <rdf:Description rdf:about="#foo">
          <dcterms:modified rdf:parseType="Resource">
            <dcterms:W3CDTF>2019-07-29T10:53:09Z</dcterms:W3CDTF>
          </dcterms:modified>
        </rdf:Description>
        <rdf:Description rdf:about="#foo"/>
        <rdf:Description rdf:about="#foo"/>
        <rdf:Description rdf:about="#foo"/>
        <rdf:Description rdf:about="#foo"/>
        <rdf:Description rdf:about="#foo"/>

Can those be removed as well? I couldn't figure out where they came from.