Contact has an override for the field JLayout. So this is expected to be different due to different JLayouts being used.

Of course trying to make them consistent would be great.

thanks for your answer. In my mind by default we shall have a structure that is common to all components. Then the developpers/integrators can use the overrides to do what they want of course.

Now for example if I want to style the fields in my website, I have to use multiple css rules depending on how joomla renders them in each page. This is not correct I think
Having by default an override has no sense for me

Really, making things simpler would be great :)

My code suggestion in the contact JLayout override

in
components/com_contact/layouts/field

<?php
/**

• @Package Joomla.Site
• @subpackage com_contact
• @copyright Copyright (C) 2005 - 2017 Open Source Matters, Inc. All rights reserved.
• @license GNU General Public License version 2 or later; see LICENSE.txt
  */
  defined('_JEXEC') or die;

if (!key_exists('field', $displayData))
{
return;
}

$field = $displayData['field'];
$label = $field->label;
$value = $field->value;
$class = $field->params->get('render_class');
$showlabel = $field->params->get('showlabel');

if (!$value)
{
return;
}

if ($field->context == 'com_contact.mail')
{
// Prepare the value for the contact form mail
echo $label . ': ' . $value . "\r\n";
return;
}

?>

<dd class="field-entry contact-field-entry <?php echo $class; ?>">
<?php if ($showlabel == 1) : ?>
<span class="field-label"><?php echo htmlentities($label, ENT_QUOTES | ENT_IGNORE, 'UTF-8'); ?>: </span>
<?php endif; ?>
<span class="field-value"><?php echo $value; ?></span>
</dd>

Since you already propose some code, can you try making a Pull Request?
Some documentation can be found here: https://docs.joomla.org/Using_the_Github_UI_to_Make_Pull_Requests

Closed as I made a PR for the above change.