Orderby taxonomy term id using get_posts not working

Question

I'm looping through a series of custom post types and then grouping those by a taxonomy term. That is working great, however I have not been able to order these groupings by term_id.

I used a var_dump to check the term_id and they are as expected. In fact, no orderby parameters are working at all - they are always ordered by the taxonomy term title. My taxonomy in this case is issue_area with terms like 'Human Services', 'Education' and so on.

What am I missing here?

Here is the loop I am using:

<?php

$terms = get_terms('issue_area'); // this is my custom taxonomy
foreach( $terms as $term ):
$termed =  preg_replace('/\d/', '', $term->name ); // split out numbers
?>                          

<h3 class="expert-term"><?php echo $termed; // Print the term name ?></h3>

<?php var_dump($term->term_id); ?> <?php // this returns an int as expected ?>

    <ul class="experts">

    <?php $posts = get_posts(array(
     'post_type' => 'uwmc_experts', // my cpt
     'taxonomy' => $term->taxonomy,
     'term' => $term->slug,
     'orderby' => $term->term_id, // tried: taxonomy_term_id
     'order' => 'ASC', // tried DESC - no change
     'numberposts' => -1,
    ));

    foreach($posts as $post): 
     setup_postdata($post); 
    ?> 

    <?php if( have_rows('experts') ): ?> <?php // acf repeater ?>

    <?php while( have_rows('experts') ): the_row(); 

        $image = get_sub_field('expert_photo');
        $content = get_sub_field('expert_bio');
        $areas = get_sub_field('areas'); ?>

        <li class="expert">

        <?php // rest of repeater loop stuff here ?>

Answer 1

Instead of trying to do this through the orderby parameter, I went a different direction.

Logically, the orderby parameter above only applies to the posts within each grouping, not the taxonomy term grouping itself so it won't work for this.

What I ended up doing was adding 01, 02, 03, etc. to the taxonomy term name itself, then stripped that out using PHP. Thus I had terms like:

01 Human Services
02 Education 
03 Financial Stability

I numbered these in the order I wanted as they won't be changing dynamically. Then I used the following to strip out the numbers from the term and echo the updated terms:

<?php
// Output all Taxonomies names with their respective items
$terms = get_terms('issue_area');
foreach( $terms as $term ):
$termed =  preg_replace('/\d/', '', $term->name );
?>                          

<h3 class="expert-term"><?php echo $termed; // Print the term name ?></h3>

Obviously a lot easier than a complex SQL query and gives me the results that I need.

Here is a live example of this: http://pressroom.uw-mc.org/meet-our-experts/

My original question has also been updated with my answer.