get_the_content not working in loop?

I am trying to modify my loop to save post data by category. I found some code on this site that saved the post’s titles based on their categories and tried to modify this to save the post’s content. However, while get_the_title and get_the_category work, get_the_content returns null.

Here is the code:

if ( false === ( $q = get_transient( 'category_list' ) ) ) {

    $args = array( 
        'posts_per_page' => -1
    );

    $query = new WP_Query($args); 

    $q = array();

    $body = array();

    while ( $query->have_posts() ) { 

        $query->the_post(); 

        $a="<a href="". get_permalink() .'">' . get_the_title() .'</a>';

        $post_id = get_the_ID();

        $post_id = $post->ID;

        $body[$post_id] = array();

        $body[$post_id]['title'] = '<a href="'. get_permalink() .'">' . get_the_title() .'</a>'; //works

        $body[$post_id]['content'] = get_the_content('Read more');

        $categories = get_the_category();

        foreach ( $categories as $key=>$category ) {

            $b = '<a href="' . get_category_link( $category ) . '">' . $category->name . '</a>';

        }

        $q[$b][] = $post_id; // Create an array with the category names and post titles

    }


    /* Restore original Post Data */
    wp_reset_postdata();

    set_transient( 'category_list', $q, 12 * HOUR_IN_SECONDS );
  }

Edit: Here is how I am using the $body array:

foreach($q[$b] as $post) {
  echo('<div class="teaser"><div class="teaser-title"><a href = "">' . $post . '</a></div><div class="teaser-text">'. $body[$post] . '</div><div class="teaser-footer"><p>pemsource.org</p></div></div>');
}

Edit2: I added the full code. When I do a var dump of body I get NULL and when I do a var dump of $q I get

array(3) { ["Conundrums"]=> array(1) { [0]=> string(64) "new post" } ["Tips and Tricks"]=> array(1) { [0]=> string(80) "Tips and tricks" } ["Uncategorized"]=> array(1) { [0]=> string(78) "Tips and Tricks" } }

seemingly regardless of how I edit the loop. I am very confused. Any help is much appreciated

echo $post->post_content; will echo your post content. Keep in mind though, it’s raw out of the database (same as get_the_content()). If you want to apply the same filters that the_content() receives, follow the instructions in the codex:

<?php
$content = apply_filters('the_content', $content);
$content = str_replace(']]>', ']]>', $content);
?>