FierceHamster54 in all reports I've seen concerning a similar error, it seems the problem was when trying to copy a folder from/to a bucket without specifying the recursive option (some were with the aws cli, but I suspect this is similar). Since the setup_aws_upload() attempts to upload a file, I suspect there's some confusion and it tries somehow to upload a folder, but does that as if it was a file... the actual implementation is providing boto3 with a Key and a Body, which should be treated as a file (although the key has no suffix) - perhaps upgrading boto will help?