Is this only when dragging files to a browser window? I suppose it hangs when reloading the browser window after the transfer completes. In other words, does it only hang when using drag and drop to upload files?
2345 solved the problem for me (I had the one with small php files).
sidenote: the about menu still shows version number 2341.
When using APPLE-J to edit a file i never run into this problem.
so i expect it has to do with dragging the file from finder to cyberduck.
in fact the files get uploaded properly, cyberduck just hangs on disconnecting.