Custom Post Type – Admin Columns

I’m not sure why you’re getting the ‘0’s. But you shouldn’t be using 2 switch statements in work_custom_columns().

Try this:

function work_custom_columns($column){
  global $post;
  switch ($column){
                 case "work_category":
                     echo get_the_term_list($post->ID, 'work_category', '', ', ','');
                 break;

                  case "work_hashtags":
                      echo get_the_term_list($post->ID, 'work_hashtag', '', ', ','');
                  break;
     }
 }