Extra character appended in csv file generated server when opening from WinSCP, via PuTTY no issues.

Extra character appended in csv file generated server when opening from WinSCP, via PuTTY no issues. Also when transferred file via WinSCP to local machine no issues.

Are those some specific characters? Or just some random garbage?

What exactly is "opening"? Do you mean editing in the WinSCP internal editor? Can you post session log file that shows correct download and reupload of the file and then editing (or whatever opening means) of the same file?