Which version you are using ?
I am getting it correct in v 8.2. One label for each input
For your reference below should be a single row of custom form layout
<tr class="form-table-group">
<td class="form-table-label-cell">$$label:CategoryID$$</td>
<td class="form-table-value-cell">$$input:CategoryID$$</td>
<td class="form-table-validation-cell">$$validation:CategoryID$$</td>
</tr>