Jasmine Protractor: Test case failing when run with grep option

I created few test cases in jasmine/protractor. When i run these using

protractor conf.js

all test case run and pass successfully.

But when i run using

protractor conf.js --grep="dummytag3"

then selected test case get executed, but it fails. I am finding it really strange that why a test case may fail with tagging and pass without tagging.

spec.js

'use strict';

var HomePage = require('./pages/homePage.js');
var BusPage = require('./pages/busPage.js');

describe('Login cases' , function() {
  var homePage= new HomePage();
  it('Login without username & password @dummytag3' , function() {
    homePage.mainLoginButtonClick();
    homePage.popupLoginButtonClick();
    expect(homePage.errMsgUsername).toEqual('Please enter valid Email or Mobile Number');
  });
 });

homePage.js

'use strict';

var HomePage = function () {
  browser.get('https://www.mobikwik.com');
  browser.driver.manage().window().maximize();
  };

 HomePage.prototype = Object.create({}, {

    //Login
    mainLoginButton: { get: function () { return element(by.id('qa-mbkLogin')); }},
    mainLoginButtonClick:   { value: function () { this.mainLoginButton.click(); }},
    popupLoginButton: { get: function () { return element(by.xpath('//*[@id="loginInfo"]/div[3]/p/button')); }},
    popupLoginButtonClick: { value: function () { this.popupLoginButton.click(); }},
    errMsgUsername: { get: function () { return element(by.xpath('//*[@id="loginInfo"]/div[1]/span')).getText(); }},


});

module.exports = HomePage;

error:

Error: Error while waiting for Protractor to sync with the page: "window.anular is undefined.  This could be either because this is a non-angular page or ecause your test involves client-side navigation, which can interfere with Protactor's bootstrapping.  See http://git.io/v4gXM for details"