I signed up and was presented with a French dashboard page. Everything was in English before. I manually changed the 'fr' in the URL to 'en' and then everything seemed to work fine :-).
I had this same experience, and between this experience and the GP comment -- how in the world is asking users to do URL surgery considered a valid UX? To say nothing of the hubris of ignoring the `accept-language:` header sent from every browser since I can remember
