Repro steps:
1) Using Mac OS X, Go->Connect To Server->https://<instance>.jira.com/webdav->connect
2) Enter admin credentials
3) Drop-drop a file into the directory

The progress bar sits on 0KB for a while, while on the server side, a 0KB file is created.
Eventually it times out.
On the client side, it reports an "Error code -36" and on the server side, the empty file disappears.