Why is this test failing? Does not seem to apply strong params correctly

A controller test fails and does not seem to apply strong params correctly. I have the following controller method:

def update
  @page = Image.find(params[:id])
  @organization = @page.organization
  if @page.update_attributes(edit_params)
    redirect_to @page
  else
    render 'edit'
  end
end

def edit_params
  list_params_allowed = [:content]
  if is_admin?(current_user, @organization) || logged_in_systemadmin?    #These helper methods work perfectly and are used throughout the app without problems. The first determines if the currently logged in user is an admin of @organization.
    list_params_allowed += [:title]
  end
  params.require(:page).permit(list_params_allowed)
end

This means that if a non-admin is logged in, he should not be able to edit the title of a page; only the content. However, the controller test below fails because a new title does get saved. Does anyone see why this is?

  test "trying to manipulate title while not admin" do
    log_in_as(@user)   # This user isn't an admin; this helper method is used in many tests and works fine
    patch :update, id: @page, page: {title: "new title", content: "new content"}
    assert flash[:success]
    @page.reload
    assert_equal @page.content, "new content"
    assert_not_equal @page.title, "new title"   # This is the line that fails
  end