Multiple Permalinks for Same Post
The request parsing is handled in WP::parse_request(). After that, there’s a action hook parse_request which gives you the instance of the wp object. We assume that http://www.example.com/my-custom-post-type/this-is-a-cool-article is your permalink and http://www.example.com/mon-type-de-poste-personnalise/cest-un-article-sympa ends up in a 404. So the first thing to check in your callback should be, if the wp object is in a …