wp_unique_post_slug does not work properly for hierarchical custom posts types
|Reported by:||chowmein||Owned by:|
|Component:||Posts, Post Types||Keywords:|
Custom post types with hierarchy set to true, will still have a suffix appended to the slug if the post name is not unique.
Currently you will have to apply the 'hierarchical_post_types' filter to your custom post type. However, this should be done through register_post_type().