Hello,
We recommend you to wrap that content using a HTML tag (such as a paragraph or a span tag), for example:
$docx->embedHTML('
<table>
<tr>
<td><br><p>First cell</p></td>
<td>Second cell</td>
<td>Third cell</td>
</tr>
<tr>
<td>2.1 cell</td>
<td>2.2 cell</td>
<td>2.3 cell</td>
</tr>
</table>
');
Or use the removeLineBreaks option:
$docx->embedHTML('
<table>
<tr>
<td><br>First cell</td>
<td>Second cell</td>
<td>Third cell</td>
</tr>
<tr>
<td>2.1 cell</td>
<td>2.2 cell</td>
<td>2.3 cell</td>
</tr>
</table>
', array('removeLineBreaks' => true));
to clean extra line breaks that may be generated by PHP Tidy.
Regards.