I created a test account on my store to play around with the templates.  I noticed that in my new account, if I go to the dashboard and select that I want to receive the newsletter, then click "Update", it doesn't appear to save.  Upon refresh, the checkmark is now gone, and when I looked in admin to manage the user, it's also un-checked.  It seems repeatable.  It does however appear to work in Admin, just not on the user end.  Might want to take a look.   I don't think I did anything to break it...