Strange result

The following sparql request on DBpedia
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
select distinct ?d
where {
        <http://dbpedia.org/resource/Toby_Moskowitz> ?p ?d .
        filter(datatype(?d)=xsd:date)
  }
gives

1971-02-03

"1971-2-3"^^<http://www.w3.org/2001/XMLSchema#date>

​Two similar values, but why both?
A lot of similar samples are present in DBPedia. Is on better than the
other?

​
--
Jean-Claude