WinSCP v6.3 SFTP issues - but FileZilla works

When connecting to a site I use all the time with WinSCP, in version 6.3, something seemed to break. When transferring file to the site now, it breaks, disconnects and the files do not get there. I had to use FileZilla to get the transfer to work properly. Interestingly, WinSCP v6.1.2 works fine. Only after upgrading to v6.3 does it break.

Thanks for your report. Please post WinSCP 6.1 and FileZilla logs too.