If I use Bulk Import on a directory where I have already imported most of the files and have renamed them, I cannot do another bulk import later on new files without getting more documents created for files that already existed. For example, if I bulk import file1.pdf and file2.pdf, this works fine. Then later, I FTP file3.pdf and file4.pdf and do another bulk import I will get a new document for file 3 and file 4, but also one or more of the existing files gets an additional document created. So I might have something like: document for file1, document for file 2, document for file 3, document for file 4, and another document for file 2.
See image for an example of a document that was re-created for a file that already existed in the directory and had already been bulk imported at a prior time.