As I understand you mentioned WinSCP attempts to connect to the server using SFTP and as you see in the attached logs that is the protocol we use. What I don't understand is why WinSCP is falling back to an SCP protocol. It shouldn't do that for us as far as i know.
There's absolutely no difference in WinSCP configuration between dvorc001 and dvorc003 logs. So it's something on the server-side.
With dvorc001 and dvorc002, the SFTP works ok.