Nope, still doesn't work. Here's a dump of the console log in case it's of any help: http://ix.io/ER9
I think it might be because you have third-party cookies disabled [1], and the Google Auth client uses an iframe with cookies to do its thing. I replicated it myself by disabling third-party cookies and the results were similar to what you described.
I'll look into what I can do about this on my end tomorrow. Thank you again for your time!