In wikidata-simple-statements triple files, there's triples such as "http://www.wikidata.org/entity/Q4318 http://www.wikidata.org/entity/P569c "-400"^^http://www.w3.org/2001/XMLSchema#gYear . ", which is wrong format. unable to parse by any rdf parser.
The -400 is wrong format, must be "-0400" for BCE Time. In addition, according to XMLS format, '-0002' of 3 BCE, and I am not sure whether wikidata noticed this. Maybe some conflicts happened.