I am trying to delete a lot of WordPress posts programmatically using
wp_delete_post, but not all posts are deleted successfully. In some cases I get
NULL as a return value for
wp_delete_post($row->post_id, true) and the post isn't deleted from the database.
There are both
page post_types amongst those not deleted posts, as well as custom post types.
What can be the issue there, why aren't some posts deleted, while many others are deleted successfully?