Problem with mapping of Materials

[DallasMuseumOfArt]

I expected to see:

Material: "Oil on Canvas"

but instead I saw:

Material is repeated: Oil on Canvas http://data.americanartcollaborative.org/dma/th... Oil on canvas http://data.americanartcollaborative.org/dma/th...

The current query was:

PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX crm: <http://www.cidoc-crm.org/cidoc-crm/>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dct: <http://purl.org/dc/terms/>
PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX schema: <http://schema.org/>

SELECT ?material_name ?lod_material_term ?material_class
WHERE {
<http://data.americanartcollaborative.org/dma/object/3070639> a crm:E22_Man-Made_Object ;
  crm:P45_consists_of ?material_class .
?material_class a crm:E57_Material ;
  skos:prefLabel ?material_name .
OPTIONAL {
 ?material_class skos:broadMatch ?lod_material_term ;
}
FILTER (!isBlank(?material_class))
}

[workergnome]

I can work around this in the browse app, but what's happening is that in the source data both spellings appear.

Our options are:

1. Treat them both as valid labels for the same concept (what we're doing now)
2. Treat them as two different concepts (probably not what you want)
3. fix this in the source data (probably the right solution, but not something that I can do.)