4a34367 created the issue

It looks like Filezilla recently started Base64 encoding passwords instead of leaving them in the clear. That's a good thing, but when Cyberduck detects the changed passwords and imports them, it gets the encrypted passwords and tries to use them in logins. Users of both applications will have an unpleasant experience when all their logins suddenly fail. I've only had this happen on my Mac but would guess it's the same on Windows.