autosubscribe-tweak.js

// Decouple updating the settings and adding the user to the mailchimplist in case of telescope settings autoSuscribe = true
// nova-newsletter/lib/callbacks.js
function updateUserNewsletterSettings (user, options) {
  if (!!Telescope.settings.get('autoSubscribe') && !!user) {
    user.telescope.newsletter_subscribeToNewsletter = true;
  }
  return user;
}
Telescope.callbacks.add("onCreateUser", updateUserNewsletterSettings);

function subscribeUserOnProfileCompletion (user) {
  if (!!Telescope.settings.get('autoSubscribe') && !!Users.getEmail(user)) {
    Meteor.call('newsletter.addEmail', user, false, function (error, result) {
      console.log(error);
      console.log(result);
    });
  }
  return user;
}
Telescope.callbacks.add("profileCompletedAsync", subscribeUserOnProfileCompletion);

// Tweak addEmail method so we can't disable the confirm email in parameters (was true by default)
// nova-newsletter/lib/server/mailchimp.js
// L35
  'newsletter.addEmail'(email, confirm = true) {
    try {
      return MailChimpList.add(email, confirm);
    } catch (error) {
      throw new Meteor.Error(500, error.message);
    }
  }

// If the user is already "marked" as subscribe, don't update his profile
// nova-newsletter/lib/server/mailchimp.js
// L133-136

      // mark user as subscribed
      if (!!user && !Users.getSetting(user, 'newsletter_subscribeToNewsletter')) {
        Users.setSetting(user, 'newsletter_subscribeToNewsletter', true);
      }
      
  

Telescope Slack discussion, check on user issue, starts around here : https://telescopeapp.slack.com/archives/general/p1465984120000353