Missing odd/even classes in first 3 rows

I use Wysiwyg with TinyMCE to create the table. I checked the HTML code and cleaned it. No matter what I do, the first 3 rows in the

section don't get assigned "odd" or "even" classes. All other rows get assigned the expected classes.

Here's the table's HTML content as generated by TinyMCE:

  <table style="width: 100%;" border="0">
    <thead>
      <tr valign="bottom">
        <td style="text-align: center;">Heading 1</td>
        <td>Heading 2</td>
        <td>Heading 3</td>
      </tr>
    </thead>
    <tbody>
      <tr valign="top">
        <td style="text-align: center;">Some text</td>
        <td>Some text</td>
        <td>&nbsp;</td>
      </tr>
      <tr valign="top">
        <td style="text-align: center;">Some text</td>
        <td>Some text</td>
        <td>&nbsp;</td>
      </tr>
      <tr valign="top">
        <td style="text-align: center;">Some text</td>
        <td>Some text</td>
        <td>&nbsp;</td>
      </tr>
      <tr valign="top">
        <td style="text-align: center;">Some text</td>
        <td>Some text</td>
        <td>&nbsp;</td>
      </tr>
      <tr valign="top">
        <td style="text-align: center;">Some text</td>
        <td>Some text</td>
        <td>&nbsp;</td>
      </tr>
    </tbody>
  </table>