Rails 4 Devise 3 confirmation token invalid when no password required

Question

I can not successfully confirm my user. Many posts have been made about an invalid token but most of them were due to the changes from Devise 2 to Devise 3. That is not my issue.

I over rid my user confirmation using https://github.com/plataformatec/devise/wiki/How-To:-Override-confirmations-so-users-can-pick-their-own-passwords-as-part-of-confirmation-activation

app/controllers/confirmations_controller.rb

class ConfirmationsController < Devise::ConfirmationsController
  # Remove the first skip_before_filter (:require_no_authentication) if you
  # don't want to enable logged users to access the confirmation page.
  skip_before_filter :require_no_authentication
  skip_before_filter :authenticate_user!

  # PUT /resource/confirmation
  def update
    with_unconfirmed_confirmable do
      if @confirmable.has_no_password?
        @confirmable.attempt_set_password(params[:user])
        if @confirmable.valid?
          do_confirm
        else
          do_show
          @confirmable.errors.clear #so that we wont render :new
        end
      else
        self.class.add_error_on(self, :email, :password_already_set)
      end
    end

    if !@confirmable.errors.empty?
      render 'devise/confirmations/new' #Change this if you don't have the views on default path
    end
  end

  # GET /resource/confirmation?confirmation_token=abcdef
  def show
    with_unconfirmed_confirmable do
      if @confirmable.has_no_password?
        do_show
      else
        do_confirm
      end
    end
    if !@confirmable.errors.empty?
      self.resource = @confirmable
      render 'devise/confirmations/new' #Change this if you don't have the views on default path 
    end
  end

  protected

  def with_unconfirmed_confirmable
    original_token = params[:confirmation_token]
    confirmation_token = Devise.token_generator.digest(User, :confirmation_token, original_token)
    @confirmable = User.find_or_initialize_with_error_by(:confirmation_token, confirmation_token)
    if !@confirmable.new_record?
      @confirmable.only_if_unconfirmed {yield}
    end
  end

  def do_show
    @confirmation_token = params[:confirmation_token]
    @requires_password = true
    self.resource = @confirmable
    render 'devise/confirmations/show' #Change this if you don't have the views on default path
  end

  def do_confirm
    @confirmable.confirm!
    set_flash_message :notice, :confirmed
    sign_in_and_redirect(resource_name, @confirmable)
  end
end

The HTML that is sent to the user for confirmation in the email is

<%= link_to 'Confirm', confirmation_url(@resource, :confirmation_token => @token) %>

The problem I am having is that initially the user is being sent to the show page since I by-passed the need for a password and no confirmation is made but no error is shown.

  # GET /resource/confirmation?confirmation_token=abcdef
  def show
    with_unconfirmed_confirmable do
      if @confirmable.has_no_password?
        do_show
      else
        do_confirm
      end
    end

When I removed the if statement to leave only

  # GET /resource/confirmation?confirmation_token=abcdef
  def show
    with_unconfirmed_confirmable do
      do_confirm
    end

The user is now sent to the confirmation New page but with the error

Confirmation token is invalid

My routes are

  as :user do
      patch '/user/confirmation' => 'confirmations#update', :via => :patch, :as => :update_user_confirmation
  end

devise_for :users, :controllers => { :confirmations => "confirmations", registrations: "registrations" } 

devise_scope :user do
  authenticated :user do
    root :to => 'devise/sessions#destroy', as: :authenticated_root
  end
  unauthenticated :user do
    root :to => 'devise/registrations#new', as: :unauthenticated_root
  end
end

Why is this token not working correctly?