A co-author currently working with these just let me know that "The montages claim to be in the head coordinate frame rather than the MRI coordinate frame". So that might cause the shift you are observing? Does it looks only like a translation issue or is there a scale issue too? It is hard to tell on the 2D rendering.
I am looking into it. Standby a moment and I'll send you and updated version so that you can check with the same code you did the previous figure.