Acceptance tests fail because after the verification link is opened, a log in is required

The register_account helper assumes that after opening the link you will just have to click the only button that's displayed on the screen.
However, as the attached screenshot shows, after opening the link, the site is requesting a log in. So now there are two buttons on the screen, and the test case fails.

Traceback (most recent call last):
  File "/mnt/jenkins/workspace/canonical-identity-provider-acceptance-dev/working/.env/local/lib/python2.7/site-packages/sst/runtests.py", line 434, in run_test_script
    exec self.code in self.context
  File "/mnt/jenkins/workspace/canonical-identity-provider-acceptance-dev/working/identityprovider/tests/acceptance/forgot_password/forgot_password_2_email_link.py", line 22, in <module>
    email_address = helpers.register_account(displayname="Fred Jones", verify=True)
  File "/mnt/jenkins/workspace/canonical-identity-provider-acceptance-dev/working/identityprovider/tests/acceptance/shared/helpers.py", line 68, in register_account
    click_button(get_element(css_class='btn'))
  File "/mnt/jenkins/workspace/canonical-identity-provider-acceptance-dev/working/.env/local/lib/python2.7/site-packages/sst/actions.py", line 1094, in get_element
    _raise(msg)
  File "/mnt/jenkins/workspace/canonical-identity-provider-acceptance-dev/working/.env/local/lib/python2.7/site-packages/sst/actions.py", line 119, in _raise
    raise AssertionError(msg)
AssertionError: Could not identify element: 2 elements found