js_options causing error

Ok - but it did used to work! The AJAX has also stopped working too - also works on my other select_advanced fields, just not the post.

Here is an example:

 $field = [
        'name' => __('Organisation', 'your-text-domain'),
        'id'   => 'select_an_org',
        'type' => 'post',
        'post_type'   => ['organisation'],
        'field_type'  => 'select_advanced',  
       // 'placeholder' => $placeholder,
       // 'aria-label'  => __( 'Select '.$orglabel, 'your-text-domain' ),
      /*  'query_args'  => [
            'post_status'    => 'publish',
           // 'posts_per_page' => 5,
            'tax_query'      => [
                [
                    'taxonomy' => 'institution-category',
                    'field'    => 'term_id',
                    'terms'    => $filterterms,
                ],
            ],
        ],*/
        'ajax'        => true, 
       // 'clone'        => true, 
       // 'max_clone' => 4,
    ];

I disabled plugins and have tested without any of the commented out extras and still not working