jQuery datatables broken table

HTML

<table id="table_id">
        
            <thead>
              <tr>
                <th scope="col">first o</th>
                <th scope="col">second</th>
              </tr>
            </thead>
        
            <tbody>
              <tr>
                <td>foo</td>
                
             <td> <span>bar</span></td>
                
            </tbody>
        
        </table>
        
        <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
        
        <link rel="stylesheet" type="text/css" href="https://cdn.datatables.net/v/dt/jszip-2.5.0/dt-1.10.18/af-2.3.0/b-1.5.2/b-colvis-1.5.2/b-flash-1.5.2/b-html5-1.5.2/b-print-1.5.2/cr-1.5.0/fh-3.1.4/r-2.2.2/datatables.min.css"/>
        <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/pdfmake/0.1.36/pdfmake.min.js"></script>
        <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/pdfmake/0.1.36/vfs_fonts.js"></script>
        <script type="text/javascript" src="https://cdn.datatables.net/v/dt/jszip-2.5.0/dt-1.10.18/af-2.3.0/b-1.5.2/b-colvis-1.5.2/b-flash-1.5.2/b-html5-1.5.2/b-print-1.5.2/cr-1.5.0/fh-3.1.4/r-2.2.2/datatables.min.js"></script>

CSS

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

#banner-message {
  background: #fff;
  border-radius: 4px;
  padding: 20px;
  font-size: 25px;
  text-align: center;
  transition: all 0.2s;
  margin: 0 auto;
  width: 300px;
}

button {
  background: #0084ff;
  border: none;
  border-radius: 5px;
  padding: 8px 14px;
  font-size: 15px;
  color: #fff;
}

#banner-message.alt {
  background: #0084ff;
  color: #fff;
  margin-top: 40px;
  width: 200px;
}

#banner-message.alt button {
  background: #fff;
  color: #000;
}

JavaScript

// adds option to copy and download in multiple formats
$(document).ready( function () {
    $('#table_id').DataTable({

    dom: 'B<"clear">lfrtip',
    buttons: {
        name: 'primary',
        buttons: [ 'copy', 'csv', 'excel', 'pdf' ]

        }}
        
    );
} );