Not tranferring multiple files

HI,
I have WinSCP version 5.17.3.0 sitting on a Windows 2016 Server.
By means of a batch file I call this to SFTP files.
It used to transfer multiple files fine, but now it seems to only do one at time.
I saw a topic about timestamps, and have the following command in the batch file which is unchanged since day one:
Is there any ideas why it will now suddenly only do one at a time, as I need to be able to do more than one at a time (typically less than 10 max).
Many thanks.

WinSCP scripts does not transfer multiple files in parallel. And it never did.

But there are other options. See for example:
Automating transfers or synchronization in parallel connections over SFTP/FTP protocol