Use d-flex instead of row for "tr" in Bootstrap 4
The thing is that "row" class takes more width then the parent container, which introduces issues.
<table class="table">_x000D_
<tbody>_x000D_
<tr class="d-flex">_x000D_
<td class="col-sm-8">Hello</td>_x000D_
<td class="col-sm-4">World</td>_x000D_
</tr>_x000D_
<tr class="d-flex">_x000D_
<td class="col-sm-8">8 columns</td>_x000D_
<td class="col-sm-4">4 columns</td>_x000D_
</tr>_x000D_
</tbody>_x000D_
</table>
_x000D_