autoloader loads class unexpectedly in classic mode

application.rb

require_relative "boot"

require "rails"
# Pick the frameworks you want:
require "active_model/railtie"
# require "active_job/railtie"
require "active_record/railtie"
# require "active_storage/engine"
require "action_controller/railtie"

ActionController::Railtie.initializer "puts default_protect_from_forgery when ActionController::Base is loaded" do
  ActiveSupport.on_load(:action_controller_base) do
    puts "default_protect_from_forgery is #{Rails.application.config.action_controller.default_protect_from_forgery}, expected: false"
  end
end

ActionController::Railtie.initializer "puts default_protect_from_forgery when application is initialized" do
  ActiveSupport.on_load(:after_initialize) do
    puts "default_protect_from_forgery is #{Rails.application.config.action_controller.default_protect_from_forgery}, expected: false"
  end
end

# require "action_mailer/railtie"
# require "action_mailbox/engine"
# require "action_text/engine"
require "action_view/railtie"
# require "action_cable/engine"
require "sprockets/railtie"
require "rails/test_unit/railtie"

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module RailsConfig
  class Application < Rails::Application
    # Initialize configuration defaults for originally generated Rails version.
    config.load_defaults 6.1

    # Configuration for the application, engines, and railties goes here.
    #
    # These settings can be overridden in specific environments using the files
    # in config/environments, which are processed later.
    #
    # config.time_zone = "Central Time (US & Canada)"
    # config.eager_load_paths << Rails.root.join("extras")

    # Don't generate system test files.
    config.generators.system_tests = nil

    config.before_configuration do
      puts "before_configuration"
    end

    config.before_initialize do
      puts "before_initialize"
    end

    config.after_initialize do
      puts "after_initialize"
    end

    initializer "before_initialize hook" do |app|
      ActiveSupport.on_load(:before_initialize) do
        puts "ActiveSupport.on_load(:before_initialize) runs at the end of before_initialize"
      end
    end

    initializer "after_initialize hook" do |app|
      ActiveSupport.on_load(:after_initialize) do
        puts "ActiveSupport.on_load(:after_initialize) runs at the end of after_initialize"
      end
    end

    puts "application.rb loaded"
  end
end

Gemfile

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '2.6.5'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails', branch: 'main'
gem 'rails', '~> 6.1.3'
# Use sqlite3 as the database for Active Record
gem 'sqlite3', '~> 1.4'
# Use Puma as the app server
gem 'puma', '~> 5.0'
# Use SCSS for stylesheets
gem 'sass-rails', '>= 6'
# Use Active Model has_secure_password
# gem 'bcrypt', '~> 3.1.7'

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
end

group :development do
  gem 'listen', '~> 3.3'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

gem 'wechat', '~> 0.12.0' # classic mode

stdout

before_configuration
application.rb loaded
before_initialize
default_protect_from_forgery is true, expected: false
config/initializers loaded
ActiveSupport.on_load(:before_initialize) runs at the end of before_initialize
after_initialize
default_protect_from_forgery is false, expected: false
ActiveSupport.on_load(:after_initialize) runs at the end of after_initialize