Hello,
I installed whole new empty instance of Joomla (3.4.1), installed latest SEBLOD, added to built-in 'Article' form field 'upload file', then created an article with an attached files, then moved it to trash, then emptied trash, and... the uploaded files are still there in the subfolders with article id. I have used standart storage for upload file field.
In my case deleting of images works great, but not files. So is there bug?