Nedb generating duplicate records

bugreport.db

{"name":"cui","encodedLicence":"someString","_id":"MQOifltLiOJh68oJ"}
{"name":"cui","encodedLicence":"someString","_id":"MQOifltLiOJh68oJ"}

bugreport.js

'use strict';

const Assert = require('assert');
const Fs = require('fs');
const filename = 'bugreport.db';

const onload = function(err) {

    if (err) {
        console.error(err);
        process.exit(1);
    }
};

const DB = require('nedb');
const db = new DB({
    autoload: true,
    filename: filename,
    onload: onload
});


const doc = {
    name: 'cui',
    encodedLicence: 'someString',
};

const options = {
   upsert: true
};


db.update({ name: 'cui' }, doc, options, (err, results) => {

    if (err) {
        console.error(err);
        process.exit(1);
    }

    Assert(results === 1);

    db.update({ name: 'cui' }, doc, options, (err, results) => {

        if (err) {
            console.error(err);
            process.exit(1);
        }
        Assert(results === 1);
        process.exit(0);

    });


});

package.json

{
  "dependencies": {
    "nedb": "^1.8.0"
  }
}