Not sure if this helps but I was having an issue where nothing was being uploaded to the folder I directed by username. I looked at the code and noticed that they are returning the wrong variable.
function cud_get_author_name($author_id){
$curuser = get_userdata($author_id);
return sanitize_title($author->user_nicename);//->display_name
}
Changing $author in the return sanitize_title function to $curuser fixed my issue.
This is on line 122 in file custom-upload-dir.php in wp-content/plugins/custom-upload-dir/ folder.
