The failure is "Cannot write more bytes to the buffer than the configured maximum buffer size: 65536.".
Ya, we should fix this. It's probably a simple setting. Maybe http://msdn.microsoft.com/en-us/library/system.net.http.httpclienthandler.maxrequestcontentbuffersize(v=vs.110).aspx
Not sure this is still relevant as our trace file sizes are more under control now.