We've noticed files overwriting themselves on migration. If you're importing two files, one named a/1.jpg and another named b/1.jpg, the basename() for both these are 1.jpg even though they are different files in different directories. I'm wondering if in plugins/destinations/fields.inc+190, if we should (a) just pass the $full_path to file_stream_wrapper_uri_normalize() or (b) further make the name unique by changing basename($full_path) to str_replace('/', '-', $full_path). Is this the right place to fix the problem and if so, which solution do you like?