the ftp server was configured to allow write-only to the folder in question.
this was done in order to ensure that the folder allows for the upload (drop off) of files.
we do not want users to download files from this folder or have information disclosure through the names of uploaded files.
the cyberduck application tries to refresh the directory after the upload and thus errors out. not a big deal if you ignore the issue but a non-technical user may be misled to believe the upload did not succeed.