rails issue reproduction: https://github.com/rails/rails/issues/6769

issue_6769.rb

require 'active_record'

ActiveRecord::Base.establish_connection adapter: "sqlite3", database: ":memory:"
ActiveRecord::Base.logger = Logger.new(STDOUT)
ActiveRecord::Schema.define do
  create_table :users do |t|
    t.timestamps
  end
  create_table :activities do |t|
    t.integer :user_id
    t.timestamps
  end
end

class User < ActiveRecord::Base
  has_many :activities, :order => "created_at desc"
end

class Activity < ActiveRecord::Base
end

u = User.create
a2 = u.activities.create
a1 = u.activities.create(created_at: 1.day.ago)
a3 = u.activities.create

users = User.includes(:activities).where("activities.created_at < ?", Time.now).to_a

expected_ids = [a3.id, a2.id, a1.id]
actual_ids = users.first.activities.map(&:id)

if expected_ids != actual_ids
  raise "Expected #{expected_ids} to match #{actual_ids}"
else
  puts "PASSED!"
end