Error: uploaded but the returned size was 0 was a recent forum report, which I found by looking for –disable-upload-verify, which I suggested after looking at the code. FTP has it too though. I don’t know why it’s better. One course of action might be to see if the newer FluentFTP code does better. It’s urgently needed anyway, because the current one breaks on current usage going to UNIX-based servers (changes the “line endings”).
EDIT:
FTP problem described here and it was one of the reasons there’s no beta yet – didn’t want this regression. Whether or not the latest FluentFTP actually fixes it is not 100% clear, so the earlier the tests of it, the better.