Steps to reproduce:
1. In some cases when a (multi-stream) mediapackage is processed I get the error message that a file already exists, and the processing fails with an error.
2. This usually happens in the second "image" operation to create the "search result preview" or a "compose" operation after the video has been trimmed or if the original video has the same filetype like one of the composed files.
3. The reason for this seems to be that a file with the same filename already exists in the workspace. The image operation creates the file with an additional postfix like "search" (compose with "-preview") but when the result is passed back to the workflow service on the admin server it get renamed. The postfix is removed and the file is only named with original base filename and the filetype ending. For a strange reason the filenames always seem to be truncated after "_." in the filename.
4. In some cases a new directory with a new UUID is created for the file and in others the directory name stays the same (for an unknown reason) or like in the image operation it is copied to an "attachment-" directory and it seems that the number for the attachment is not increased like expected.