Surprisingly, I could not find an Issue about this #DBpedia problem. Now there is one: https://github.com/dbpedia/extraction-framework/issues/820

Contrary to my initial guess of an extractor bug, further investigations made an SPARQL endpoint (#openlinksw #virtuoso) bug seem more likely.

Missing `rdf:type`s in HTML view and in some SPARQL answerse · Issue #820 · dbpedia/extraction-framework

Issue validity Could not check, due to DIEF ERROR 502 response. Error Description Many resources are missing some rdf:type statements. Pinpointing the source of the error It affects the SPARQL (htt...

GitHub
Oh nice a new #openlinksw #virtuoso release coming! https://github.com/openlink/virtuoso-opensource/commit/5cf13cd06c131c25043c4b6525eee46455a606ca looks it will have some nice fixes and improvements.