Hi,
Well, there are a few unneccesary lines there, as well as I am not sure the the wp_get_post_categories returns the array of category IDs by default. Try this modification:
add_filter("asp_query_args", "asp_query_args_change", 10, 2);
function asp_query_args_change($args, $search_id) {
$post_id = $args['_page_id'];
if ($search_id == 3) {
$args['post_type'] = array('post');
$args['post_fields'] = array('title', 'content', 'excerpt', 'terms');
$args['post_tax_filter'] = array(
array(
'taxonomy' => 'category',
'include' => wp_get_post_categories($post_id, 'ids')
)
);
}
return $args;
}