Please post logs from both.
Yes, unfortunately it also occurs there, but not as often and persistently as with WinSCP.
Thanks for your report. Do you have any reason to believe that it's WinSCP's problem? Did you try other SFTP clients? Don't they lose the connection too?
The connection to the server is unstable. WinSCP repeatedly loses the connection when opening files or switching directories. Disconnects occur at irregular intervals, ranging from approximately 5 seconds up to 10 minutes.