Nearley's own grammar is ambiguous?

[Antony74]

const fs = require('fs');
const nearley = require('nearley');
const grammar = require('nearley/lib/nearley-language-bootstrapped');

const parser = new nearley.Parser(nearley.Grammar.fromCompiled(grammar));

const text = fs.readFileSync(
    'node_modules/nearley/lib/nearley-language-bootstrapped.ne',
    { encoding: 'utf-8' }
);

parser.feed(text);
parser.finish();

console.log(parser.results.length);

EXPECTED: 1
ACTUAL 2