Recibo este error sobre mi archivo de rutas

SystemStackError (stack level too deep):
  actionpack (3.2.8) lib/action_dispatch/middleware/reloader.rb:70


  Rendered /Users/duy/.rvm/gems/ruby-1.9.3-p194/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.5ms)
  Rendered /Users/duy/.rvm/gems/ruby-1.9.3-p194/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (1.3ms)
  Rendered /Users/duy/.rvm/gems/ruby-1.9.3-p194/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (19.9ms)

Podría aislar el código problemático pero no entiendo qué está creando el bucle infinito:

  devise_for :users, :controllers => { :registrations => "registrations", :sessions => "sessions", :omniauth_callbacks => "users/omniauth_callbacks" }
  devise_scope :user do
    match '/sessions/simulate_user/:id' => 'sessions#simulate_user', :as => :simulate_user_sessions
    match '/sessions/leave_simulation_mode' => 'sessions#leave_simulation_mode', :as => :leave_simulation_mode_sessions
    get "user_confirmation", :to => "devise/confirmations#create"
    get "after_confirmation", :to => "challenges#index"
  end

Cualquier ayuda sería muy apreciada!

EDITAR:

class SessionsController < Devise::SessionsController

  def new

    @after_sign_in_page = params[:after_sign_in_page] if params[:after_sign_in_page]
    super
  end

  def create
    params[:user][:email].downcase!
    super
  end

  def simulate_user
    if can? :simulate_user, User
      admin = current_user.id
      sign_out
      @user = User.find(params[:id])
      if sign_in @user
        session[:simulation_for] = admin
        redirect_to request.referer
      else
        flash[:notice] = "Something went wrong"
        redirect_to action: "leave_simulation_mode"
      end
    end
  end

  def leave_simulation_mode
    @user = User.find(session[:simulation_for])
    sign_out
    if sign_in @user
      session[:simulation_for] = nil
    else
      flash[:notice] = "something went wrong..."
    end
    redirect_to request.referer
  end

end
class ChallengesController < ApplicationController
      def index
        params[:format] = "html" unless params[:subaction].nil?
        @video = true unless user_signed_in?
        if current_user
          @current_page = params[:page] ? params[:page].to_i : 1
          @columns = params[:cols] ? params[:cols] : 2
          @keyword = params[:keyword]
          @search = true if params[:search] == "1"
          @challenges = Challenge.is_open.where(id: current_user.challenges.filtered(params[:keyword],params[:user],params[:expertize]).collect(&:root_id).uniq)
          logger.debug "Challenges found: #{@challenges.count}"
          @users = User.scoped
          @expertizes = Expertize.all
        end

        respond_to do |format|
          format.html {
            if current_user
              if current_user.challenges.waiting_for_approval.count == 1 and @challenges.count == 1
                redirect_to challenge_path(current_user.challenges.waiting_for_approval.first, subaction: "description")
                return
                logger.debug "REdirect called"
              else
                @challenges = @challenges.page(1).per(@current_page.to_i * 10).order('children_count+tasks_count desc')
              end
            end
            render
            }
          format.json { render json: @challenges }
          format.js {
            @challenges = @challenges.page(@current_page).per(10).order('children_count+tasks_count desc')
            render
          }
        end
      end
end

Además, olvidé mencionar que cuando reinicio el servidor local, funciona bien. Cada vez que cambio mi archivo route.rb, aparece este error. Luego tengo que reiniciar el servidor Thin, luego puedo trabajar más en ...

EDIT 2:

Salida de ruta de rake:https://www.dropbox.com/s/knmkk1f54vx47yj/rake%20routes.rtf