I had the same problem. After upgrading to WP 4.0 only sticky topics were visible. I tried the patch/plugin “bbpress wp4 fix”. I could now see all topics, but when I clicked on any one of them only the first forum topic would open. The URL was correct, but the wrong topic appeared in the page. I deactivated the plugin and after some more research, found that I had a piece of code in my functions file that interfered with the topics showing. Here is the code that caused the problem:
//exclude from search results
function fb_search_filter($query) {
if ( !$query->is_admin && $query->is_search) {
$query->set('post_type', array('course_unit') ); // id of page or post
}
return $query;
}
add_filter( 'pre_get_posts', 'fb_search_filter' );
I don’t know why this code is a problem, but I no longer needed it. I deleted it and now my forums are working just fine.
