元查询按值排除

I have a problem. I'm trying to exclude categories by there term meta. In my date base table I have

meta_id | term_id |        meta_key        | meta_value |
---------------------------------------------------------
   1    |    12   | term_category_realized |      1
---------------------------------------------------------
   2    |    20   | term_category_realized |      2

I'm setting up my args like this:

      <?php
        $args = array(
            'show_option_all'    => '',
            'orderby'            => 'ID',
            'order'              => 'ASC',
            'meta_query' => array(
               array(
                  'key'       => 'term_category_realized',
                  'value'     => 1,
                  'compare'   => '!='
               )
             )
        );
        ?>

and I get no result in the query. Whenever I change the 1 to 2 I get one result. Why is this not working with meta_value 1?

the foreach loop I use to output the results

echo '<ul class="realized-projects-category-list">';
          foreach($categories as $category) {
             echo '<li>';
              echo '<a href="' . get_category_link($category->term_id) . '">' . $category->name . '</a>';
             echo '</li>';
          }
        echo '</ul>';

UPDATE I have added some more categories. The problem occurs only to the term_id 20. Other categories are shown.