Please attach a full session log file showing the problem (using the latest version of WinSCP).
This issue existed throughout all the versions...
To generate the session log file, enable logging, log in to your server and do the operation and only the operation that causes the error. Submit the log with your post as an attachment. Note that passwords and passphrases not stored in the log. You may want to remove other data you consider sensitive though, such as host names, IP addresses, account names or file names (unless they are relevant to the problem). If you do not want to post the log publicly, you can mark the attachment as private.
None of this really related. This happens in every FTP host site, with different IP addresses, and the operation in question is just downloading! And the issue is nor user initiated.
I start the download and sometime in next minutes or other times in hours, it happens.
I will provide three messages here. They all waited for me to arrive to click on the 'Continue' button. Then it resumed right away. This issue also occurs while I attend the process and then which I click the 'Continue' button immediately and so it does...