FTP transfer using a batch file

I am trying to transfer files from FTP to FTP via a batch file but it loses a few KBs when copying. So, if the file size was 400kb then it would copy 396kb. I have ran the batch file multiple times but I am still experiencing the same issue. I then clicked the option for "Compare Directories" within the software but it "No differences found".
I would also like to verify the copied files using the batch files. Is there a way to do so?
I have attached the code with the post

Please attach a full session log file showing the problem (using the latest version of WinSCP).

I am not sure why it didn't post earlier but here it is.

There's no file transfer in the log you have posted:

< 2023-09-11 11:30:03.445 Script: Nothing to synchronize.

That is the issue. Even though the files are not transferred correctly, it keeps saying there is nothing to synchronize via the code and the WinSCP software.

So please go back to the original problem. Post a log file showing the copy that "loses a few KBs".

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Or if you want WinSCP to recognize that the file is not complete during synchronization, include file size into synchronization criteria:
https://winscp.net/eng/docs/scriptcommand_synchronize#criteria