Changes

    headers = { 'Accept': 'application/sparql-results+json' };

    headers = { 'Accept': 'application/sparql-results+json' };

    debug("qid: "+ qid + "\ntypeqid: " + typeqid + "\n" + fullUrl + "\n" + sparqlQuery);

    debug("qid: "+ qid + "\ntypeqid: " + typeqid + "\n" + fullUrl + "\n" + sparqlQuery);

        fetch( fullUrl, { headers } ).then( body => body.json() ).then( json => {

        fetch( fullUrl, { headers: { 'Accept': 'application/sparql-results+json' } } )

    if ( json.boolean )

        .then( body => body.json() )

        quickpresets_addinterface(qid, prop);

        .then( json => { if ( json.boolean ) quickpresets_addinterface(qid, prop); } );

      } );

    }

    }

     }

     }