Box.getAccountTree returns null / "unknown http status"

After the first call to Box.getAccountTree, subsequent calls result in the onComplete handler being called with a null BoxFolder, and the status "unknown http status" (or whatever the appropriate constant actually contains).

This behaviour is not documented anywhere noticable

The behaviour is a result of the HttpUrlConnection in BoxSynchronous.saxRequest having 'useCaches' turned on, which causes conn.getResponseCode() to return -1.
Adding conn.setUseCaches(false); to this method before conn.connect(); results in the http request always getting executing, and a BoxFolder always being passed to onComplete.