Mongoid embeds_many bug - loses create after some some destroy_all/create sequences

Mongoid_embeds_many_destroy_all_bug

require 'rubygems'
require 'mongoid'
require 'rspec'
require 'method_lister'

Mongoid.configure do |config|
  name = "association_bug"
  config.master = Mongo::Connection.new.db(name)
end

class Commit
  include Mongoid::Document
  embeds_many :tasks
end

class Task
  include Mongoid::Document
  embedded_in :commit, :inverse_of => :tasks
end

def show_methods(object)
  puts (object.methods.sort - Object.new.methods).join(", ")
end

describe Commit do
  before do
    @commit = Commit.create
  end

  it "passes" do
    @commit.tasks.destroy_all
    @commit.tasks.create
    @commit.tasks.destroy_all
    @commit.tasks.create
  end
  
  it "passes" do
    @commit.tasks.destroy_all
    @commit.tasks.create
    @commit.tasks.create
    @commit.tasks.create    
  end

  it "fails" do
    @commit.tasks.create
    @commit.tasks.create
    @commit.tasks.destroy_all
    @commit.tasks.create # this call fails
  end
end