[@vojtasvoboda Participant 11 years, 7 months ago]

When I debuged WP_Query in bbpress/includes/topics/template.php on line 203, it prints:

SELECT SQL_CALC_FOUND_ROWS  wp_2_posts.ID FROM wp_2_posts  INNER JOIN wp_2_postmeta ON ( wp_2_posts.ID = wp_2_postmeta.post_id ) WHERE 1=1  AND wp_2_posts.post_parent = 5080  AND wp_2_posts.post_type = 'post' AND (wp_2_posts.post_status = 'publish' OR wp_2_posts.post_status = 'closed' OR wp_2_posts.post_status = 'private' OR wp_2_posts.post_status = 'hidden') AND ( 
  wp_2_postmeta.meta_key = '_bbp_last_active_time'
) GROUP BY wp_2_posts.ID ORDER BY wp_2_postmeta.meta_value DESC LIMIT 0, 15

with post_type=post, but it should be post_type=topic. Damn.