Why does AngularJS controller fire twice?

Question

JavaScript

There is a controller with the following content

app.controller("ProductListCtrl", ['$scope', 'Products', 'Product', function($scope, Products, Product) {
  console.log("ProductListCtrl");
  $scope.sortType      = 'name';
  $scope.sortReverse   = false;
  $scope.searchProduct = '';
  $scope.products = Products.query();
  $scope.deleteProduct = function (id) {
    if (confirm("Are you sure you want to delete this Product?")){
      console.log(id);
      Product.delete({id: id}, function(){
        $scope.products = Products.query();
      });
    }
  }
}]);

And every time when it works (except the first one) console.log("ProductListCtrl"); is displayed in the console 2 times.
Why???
Here are more routes

'use strict';

var app = angular.module('app', ['ngRoute', 'ngResource']); 

//Routes
app.config([
  '$routeProvider', function($routeProvider, $locationProvider) {
    $routeProvider
    .when('/', {
      templateUrl: 'templates/index.html',
      controller: 'ProductListCtrl'
    })
    .when('/products/new', {
      templateUrl: 'templates/new-product.html',
      controller: 'ProductNewCtrl'
    })
    .when('/products/:id/edit', {
      templateUrl: 'templates/edit-product.html',
      controller: 'ProductEditCtrl'
    })
    .when('/products/:id', {
      templateUrl: 'templates/detail-product.html',
      controller: 'ProductDetailCtrl'
    })    ;
    
    $routeProvider.otherwise({
      redirectTo: '/products',
      templateUrl: 'templates/index.html',
      controller: 'ProductListCtrl'
    });
  }
]);

and services

'use strict';

var app = angular.module('app');

app.factory('Products', ['$resource',function($resource){
  return $resource('/products', {},{
    query: { method: 'GET', isArray: true },
    create: { method: 'POST' }
  })
}]);

app.factory('Product', ['$resource', function($resource){
  return $resource('/products/:id', {}, {
    show: { method: 'GET' },
    update: { method: 'PUT', params: {id: '@id'} },
    delete: { method: 'DELETE', params: {id: '@id'} }
  });
}]);

Answer 1

en.stackoverflow.com/a/429516

Answer 2

because controllers in angular are instantiated on each visit to the state or redrawing the view (when an element is removed from the Dom and added.
That is, you can’t catch the problem from the given piece. You need to watch how you use this case.