WP Slug Customization gives Error 404 / Not found (PODs Custom Post Types)

I am using PODs custom post type and I have created bi-relatation between two post types. My idea is to get a custom slug when there is a relation between two custom post types like: /custom-post-slug1/custom-post-slug2/post-title

So I have created this function:

function custom_post_slug ( $post_link, $post ) {

}
add_filter( ‘post_type_link’, ‘custom_post_slug’, 10, 3 );

The function does work (I could see that slug got modified, but I am getting 404/not found on post pages….). Am I missing something?

Thanks!