Uploading multiple files fails with write-only permissions on sftp server

Goodmorning,

we're using a script to upload multiple files to an sftp server. This scripts works exept with one sftp server, where we only have write-only permissions. It will upload the first file, but after that all file uploads fails.

We make use of UploadFileByName. Please find below logfile. It looks like it tries to open the file. Does anybody know why it tries to open the file and if we can prevent this?

 localFileSize: 0
  sftpOpenFile:
    remotePath: //in/test4.txt
    access: writeOnly
    createDisposition: createTruncate
    v3Flags: 0x1a
   Sent FXP_OPEN
    StatusResponseFromServer:
      Request: FXP_OPEN
      InformationReceivedFromServer:
        StatusCode: 3
        StatusMessage: Permission denied
      --InformationReceivedFromServer
    --StatusResponseFromServer
    retryFilepath: .//in/test4.txt
    remotePath: .//in/test4.txt
    access: writeOnly
    createDisposition: createTruncate
    v3Flags: 0x1a
    Sent FXP_OPEN
    StatusResponseFromServer:
      Request: FXP_OPEN
      InformationReceivedFromServer:
        StatusCode: 3
        StatusMessage: Permission denied
      --InformationReceivedFromServer
    --StatusResponseFromServer
  --sftpOpenFile
  Failed to open file.
--uploadFileByName
Failed.   --UploadFileByName

--ChilkatLog