Table multi cells not working

Hello,

It seems that tables with cells over multiple columns are not properly working. The colspan attribute has no effect. It is the case with the bootstrap example below :

<table class="table">
  <thead>
    <tr>
      <th scope="col">#</th>
      <th scope="col">First</th>
      <th scope="col">Last</th>
      <th scope="col">Handle</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <th scope="row">1</th>
      <td>Mark</td>
      <td>Otto</td>
      <td>@mdo</td>
    </tr>
    <tr>
      <th scope="row">2</th>
      <td>Jacob</td>
      <td>Thornton</td>
      <td>@fat</td>
    </tr>
    <tr>
      <th scope="row">3</th>
      <td colspan="2">Larry the Bird</td>
      <td>@twitter</td>
    </tr>
  </tbody>
</table>

Result :

The text "Larry the Bird" should be centered between the two first columns but it is stuck to left.

I tried to reinstall the most recent bootstrap version (7.1) manually but it didn't solve the problem.

Would you have any idea where it comes from ?