BUG: "Keep remote directory up to date" fails

Version 4.1.9 build 416, to latest betas.
Protocol: SFTP-3
Local OS: Windows 7 beta 7100
Remote OS: Debian 4
Remote FTP Server Daemon: vsftpd

Option "keep remote directory up to date" should upload changed files onto remote server. In most cases it does so, but sometimes it fails without any reason, randomly.

In sychronization window I can read "Change in ... detected..." twice. But no upload occurs.

When I manually try to upload the file, I get permission error, but the file is uploaded correctly, with correct permissions. I use group permission for writing. SFTP user is in group which has write access. The owner is different, and it should be different. The directory has owner set to my client user, I apply MY changes as 'www' user.

This bug seems to be permanent, feature seems plain broken.

In other directories, when user is equal to owner uploading sometimes work, sometimes not. Mostly works. It's very frustrating to fix non-existing bugs in my code just because WinSCP randomly refuses to upload changed files.

Will send you debug version soon.

If it could help - I've switched "environment" option "adjust remote timestamp with DST (Windows)" and now it seems to work. My remote server uses GMT time, but when I logon with shell (via putty) - it shows correct timestamps with mc (or ls). With "adjust remote timestamps with local conventions (Unix)" all timestamps were one hour ahead. I think this was the reason. On the other hand - I changed most of the files with WinSCP and it's still strange why this problem didn't occur before. It seems to sometimes work ok and sometimes not. I haven't figured it why yet, but I'm trying. Sometimes even restarting WinSCP helped.

Have you read this FAQ?

Well. My fault, I haven't. Shame on me. But from the start I didn't even notice it was a timestamp problem, WinSCP did detect a file changed, just ignored the change. If it was able to detect the change - it should still upload the file, right?

No. Please read how the function works.