Testacular freezes when navigating outside the AngularJS base path

I have an AngularJS application that requires authentication. It's part of a larger project served from Express and lives at its own base path: <base href="/path/to/app/">, not /. The existing application already has a round trip login. Users need to be logged in before they can access the Angular app. This works fine, except for e2e testing with testacular.

With authentication on the server disabled, e2e tests run without problems. For example:

describe 'protected app', ->

  it 'should display the index', ->
    browser().navigateTo '/path/to/app'
    expect(browser().location().url()).toBe '/'

  it 'etc...'

Obviously, with server side authentication, this will fail. We need to be logged in first. We get the following error:

Sandbox Error: Application document not accessible.

The problem comes when we try to log in within our scenarios.

describe 'protected app', ->

  it 'should authenticate', ->
    browser().navigateTo '../login'
    #input('#email').enter('admin@example.com')
    #input('#password').enter('secret')
    #element('button').click()    

  it 'should display the index', ->
    browser().navigateTo '/path/to/app'
    expect(browser().location().url()).toBe '/'

  it 'etc...'

Running this (with or without filling out the form and clicking) results in the login page loading and freezing up. Testacular never completes its run, it just hangs on the login page.

Is there a flaw in my understanding of Angular/Testacular/e2e testing or perhaps a bug?