Show bug in jspdf

<!DOCTYPE html>
<html>

<head>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.0.272/jspdf.debug.js"></script>
  <script>
    function makePDF() {
      var doc = new jsPDF();
      doc.text(20, 20, 'Hello worlsd!');
      return doc;
    }

    function save() {
      var doc = makePDF();
      doc.save('test.pdf');
    }

    function saveCorrupt() {
      var doc = makePDF();
      doc.output('dataurlstring');
      doc.save('test.pdf');
    }
    
    function showLengthDiff() {
      var doc = makePDF();
      var blob = doc.output('blob');
      document.body.innerHTML += '<p>Blob length first run: ' + blob.size + '</p>';
      blob = doc.output('blob');
      document.body.innerHTML += '<p>Blob length second run: ' + blob.size + '</p>';
    }
  </script>
</head>

<body>
  <button onclick="save()">Download PDF</button>
  <button onclick="saveCorrupt()">Download Corrupt PDF</button>
  <button onclick="showLengthDiff()">Show blob lenght diff</button></body>

</html>