Ember.js - ENV.host setting being ignored - how can I diagnose this?

I've got two very similar, and simple, apps.

I start both of them as 'ember s' with no other arguments.

They both rely on a backend found at http://localhost:8000 .

One of them works perfectly the other is convinced it should be making API calls to http://localhost:4200 .

So for instance rendering a list screen on the working one involves a GET to http://localhost:8000/api/todos . Rendering a list screen on the non-working one results in a GET request being made to http://localhost:4200/api/projects .

The location of the backend is defined in config/application.js via the ENV.host property.

How can I further diagnose this problem to see why the non-working app ignores ENV.host ?

Any ideas welcome.

I'll put the relevant configs below in case that helps.

---

The problem config/application.js looks like this :

module.exports = function(environment) {
  var ENV = {
    host: 'https://example.com',
    modulePrefix: 'spuv-ember',
    environment: environment,
    baseURL: '/',
    locationType: 'auto',
    EmberENV: {
      FEATURES: {
        // Here you can enable experimental features on an ember canary build
        // e.g. 'with-controller': true
      }
    },

    APP: {
      // Here you can pass flags/options to your application instance
      // when it is created
    }
  };

  if (environment === 'development') {
    // ENV.APP.LOG_RESOLVER = true;
    // ENV.APP.LOG_ACTIVE_GENERATION = true;
    // ENV.APP.LOG_TRANSITIONS = true;
    // ENV.APP.LOG_TRANSITIONS_INTERNAL = true;
    // ENV.APP.LOG_VIEW_LOOKUPS = true;
       ENV.host = 'http://localhost:8000';
  }

  if (environment === 'test') {
    // Testem prefers this...
    ENV.baseURL = '/';
    ENV.locationType = 'none';

    // keep test console output quieter
    ENV.APP.LOG_ACTIVE_GENERATION = false;
    ENV.APP.LOG_VIEW_LOOKUPS = false;

    ENV.APP.rootElement = '#ember-testing';
  }

  if (environment === 'production') {

  }

  return ENV;
};

The working config\application.js looks like this :

module.exports = function(environment) {
  var ENV = {
    host: 'https://example.com',
    modulePrefix: 'todo-ember',
    environment: environment,
    baseURL: '/',
    locationType: 'auto',
    EmberENV: {
      FEATURES: {
        // Here you can enable experimental features on an ember canary build
        // e.g. 'with-controller': true
      }
    },

    APP: {
      // Here you can pass flags/options to your application instance
      // when it is created
    }
  };

  ENV['ember-simple-auth'] = {
    authenticationRoute: 'login',
    routeAfterAuthentication: 'todos',
    routeIfAlreadyAuthenticated: 'todos'
  };

  if (environment === 'development') {
    ENV.host = 'http://localhost:8000';
    // ENV.APP.LOG_RESOLVER = true;
    // ENV.APP.LOG_ACTIVE_GENERATION = true;
    // ENV.APP.LOG_TRANSITIONS = true;
    // ENV.APP.LOG_TRANSITIONS_INTERNAL = true;
    // ENV.APP.LOG_VIEW_LOOKUPS = true;
  }

  if (environment === 'test') {
    // Testem prefers this...
    ENV.baseURL = '/';
    ENV.locationType = 'none';

    // keep test console output quieter
    ENV.APP.LOG_ACTIVE_GENERATION = false;
    ENV.APP.LOG_VIEW_LOOKUPS = false;

    ENV.APP.rootElement = '#ember-testing';
  }

  if (environment === 'production') {

  }

  return ENV;
};