Why does Session#Destroy trigger not_authenticated action?

[slava-nikulin]

class UserSessionsController < ApplicationController
  skip_before_action :require_login, except: [:destroy]

  def new
    ...
  end

  def create
    ...
  end

  def destroy
    logout
    redirect_to signin_path , flash: { info: 'Bye!' }
  end
end

class ApplicationController < ActionController::Base
  before_action :require_login

  private
  def not_authenticated
    redirect_to signin_path, flash: { danger: "ALARM!" }
  end
end

After I logout, I'm redirected to sign in page with flash message "ALARM".
After that, when I log in again I'm redirected to sign in page with flash message "Bye!"
Please, help!