Hi,
It's by design. If you want to change that, you would have to change the code:
$variant->characteristics_text .= $separator . $val->characteristic_value;
to:
$db = JFactory::getDBO();
$db->setQuery('SELECT characteristic_value FROM #__hikashop_characteristic WHERE characteristic_id='.$db->Quote($val->characteristic_parent_id));
$name = $db->loadResult();
$variant->characteristics_text .= $separator . $name.' '.$val->characteristic_value;
in the file administrator/components/com_hikashop/classes/product.php