Sometimes you want to build a page with various custom posts displayed on the same page and use one of these post’s comments to handle the page comments. However, when you submit a comment associate with a given post, the submit button redirects you to that post’s permalink, and not to your original page. To overcome this, you need to filter the redirect location such as,

add_filter( 'comment_post_redirect', 'redirect_comments', 10,2 );
function redirect_comments( $location, $commentdata ) {
  if(!isset($commentdata) || empty($commentdata->comment_post_ID) ){
    return $location;
  }
  $post_id = $commentdata->comment_post_ID;
  if('my-custom-post' == get_post_type($post_id)){
    return wp_get_referer()."#comment-".$commentdata->comment_ID;
  }
  return $location;
}

Don’t forget to also change the ‘Reply’ button links on comments using the filter comment_reply_link