Hello,
MS Word can handle a limited number of columns with automatic widths. As general recommendation (https://www.phpdocx.com/documentation/cookbook/convert-html-to-word) when importing HTML with tables, please set the cell widths of at least the first row, and they will appear correctly in all DOCX readers. For example using width attributes:
$html = '
<table>
<tr><td width="100">1</td><td width="100">2</td><td width="100">3</td><td width="100">4</td><td width="100">5</td></tr>
<tr><td>6</td><td colspan="3">7</td><td>8</td></tr>
</table>
';
$docx->embedHTML($html);
Or CSS styles:
$html = '
<style>
table tr:first-child td {
width: 50px;
}
</style>
<table>
<tr><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td></tr>
<tr><td>6</td><td colspan="3">7</td><td>8</td></tr>
</table>';
$docx->embedHTML($html);
Regards.