I had a similar problem where the checkbox had been checked, creating the key, and then being unchecked at a later time. I seemed to have fixed it with this (‘rented’ is the checkbox field):
'meta_query' => array(
'relation' => 'AND',
array(
'key' => 'status',
'value' => 'active',
),
array(
'relation' => 'OR',
array(
'key' => 'rented',
'value' => '1',
'compare' => '!='
),
array(
'key' => 'rented',
'value' => '1',
'compare' => 'NOT EXISTS'
)
)
)
This should work for you. Make the field name ‘the_content’. I am wrapping this up into a plugin and will also include the_excerpt, and featured_image.
function hg_acf_save_content( $value, $post_id, $field )
{
wp_update_post( array( 'ID' => $post_id, 'post_content' => $value ) );
return $value;
}
add_filter('acf/update_value/name=the_content', 'hg_acf_save_content', 10, 3);