LS does not show files that other FTP clients do

I have an FTP site which does not return a file on an "ls" operation. Other clients (FileZilla, Windows FTP) do return the file I am expecting and that does exist on the remote site. Here is the log from FileZilla in which the expected file(s) are successfully shown. Yes, I have tried a "get" of the file outright. Is this a limitation with WinSCP and the FTP proxy on the remote end?

Status: Connection established, waiting for welcome message...
Response: 220 txdmzpxy01 FTP proxy (Version V2.1) ready.
Command: USER <omitted>
Response: 331-(----GATEWAY CONNECTED TO <omitted>----)
Response: 331-(220 <<<Connect:Enterprise UNIX 2.4.02 Secure FTP>>> at tx2spdts01 FTP server ready. Time = 16:12:27)
Response: 331 Password required for <omitted>.
Command: PASS ********
Response: 230 Connect:Enterprise UNIX login ok, access restrictions apply.
Command: SYST
Response: 215 UNKNOWN Type: L8
Command: FEAT
Response: 500 command not understood
Status: Connected
Status: Retrieving directory listing...
Command: PWD
Response: 257 "/<omitted>" is current directory.
Command: TYPE I
Response: 200 Type set to I.
Command: PASV
Response: 227 Entering Passive Mode (<OMITTED>)
Command: LIST
Response: 150 Opening BINARY mode data connection for .
Response: 226 Transfer complete.
Status: Directory listing successful

Can you post or email me a complete log file of both WinSCP and Filezilla?