Attempting to set file time/date and permissions results in error for files with accented characters

I have the latest version of freeSSHd running on a Win 8.1 Pro (x64) box and am connecting to it via SFTP using WinSCP v.5.7.4 from machines running Win 7 Pro (both x86 and x64). In WinSCP, I have enabled UTF-8 encoding for file names which results in remote file names being displayed correctly if they contain accented characters (e.g. "é", "è", "š", etc.). However, setting file modification time/date and file permissions after any such file has been transferred _to_ the server results in an error message "File or folder does not exist. Error code: 2. Error message sent by server: No such file." (Transferring the same file _from_ the server produces no error message.)

In other words, there are two possible scenarios while uploading files:

(A) No accented characters in file name:
File transfer to server: successful
Setting file time/date and permissions after transfer: successful

(B) Accented characters (e.g. "é", "è", "š", etc.) in file name:
File transfer to server: successful
Setting file time/date and permissions after transfer: ERROR (server responds with message "No such file")

It looks like a bug in the freeSSHD (it's pretty buggy server overall).
Did you try another SFTP client?