That's by purpose. This is error from which WinSCP can recover (reconnect and resume transfer), so it tries that.

You can disable this by setting option reconnecttime to short interval.
https://winscp.net/eng/docs/scriptcommand_option

Script:
# Automatically abort script on errors
option batch abort
# Disable overwrite confirmations that conflict with the previous
option confirm off
# Connection
open ftp://Firma064:meZ15(J1)d@217.7.154.116 -passive=on
# Change remote directory
cd /Orders/test
# Upload the file to current working directory
put F:\EDI\VIEGA\OUT\ORDER\*.txt
# Disconnect
close
# Exit WinSCP
exit


Command:
winscp.com /script="F:\WINSCP\EDI\VIEGA\UPLOAD.TXT" /log="F:\WINSCP\EDI\VIEGA\upload.log"

Output:
batch abort
confirm off
Connecting to 217.7.154.116 ...
Connected with 217.7.154.116. Waiting for welcome message...
Connected
Starting the session...
Reading remote directory...
Session started.
Active session: [1] Firma064@217.7.154.116
/Orders/test
F:\...\8601827122.txt | 0 B | 0,0 KiB/s | binary | 0%
Lost connection.
Timeout detected.
Copying files to remote side failed.
(A)bort, (R)econnect (1 s):


WinSCP, Version 5.5.0 (Build 3839)


What am I doing wrong?[/u]