I'm having a problem where sometimes, apparently nondeterministically, WinSCP claims thta the host key verification fails, even though the Ed25519 host key fingerprint it shows as "new" is exactly the same as the one it has saved.
Please see the attached screenshot, which displays that in fact the two keys are the same.
The key also agrees with what the server's fingerprint actually is.
The problem happens when doing large batch transfers of 100 GB toal with ~1GB individual file size, "background transfer" is active, and up to 9 files are being transferred in parallel.
If I click "Update", I get the "Host is not communicating for more than 15 seconds", with an "Abort" button that counts down seconds that reset from 57 back to 60 every 3 seconds approximately. Eventually, the Abort button will not have a seconds counter any more, and just be labelled "Abort", when I click that, I get a password prompt popup, even though I have configured the Site in WinSCP to use key-based login.
WinSCP 5.19 (Build 11512) on Windows Server 2019. Target host is openssh-8.2p1.
This looks like a bug to me.