accepts_nested_attributes_for '_delete' feature broken in Rails 2.3.8

I created Rails 2.3.8 test application:

class User < ActiveRecord::Base
  has_many :addresses
  accepts_nested_attributes_for :addresses, :allow_destroy => true
end

class Address < ActiveRecord::Base
  belongs_to :user
end

Then I try to delete some nested object:

ruby script/console 
Loading development environment (Rails 2.3.8)
>> u = User.create(:name => "Max")
=> #<User id: 1, name: "Max", created_at: "2010-05-26 14:16:12", updated_at: "2010-05-26 14:16:12">
>> u.update_attributes(:addresses_attributes => {'0' => {:city => 'York'}})
=> true
>> u.update_attributes(:addresses_attributes => {'0' => {:id => '1', :city => 'York'}})
=> true
>> u.addresses
=> [#<Address id: 1, country: nil, city: "York", street: nil, user_id: 1, created_at: "2010-05-26 14:16:46", updated_at: "2010-05-26 14:16:46">]
>> u.update_attributes(:addresses_attributes => {'0' => {:id => '1', :city => 'York', '_delete' => '1'}})
ActiveRecord::UnknownAttributeError: unknown attribute: _delete
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2906:in `assign_attributes'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2902:in `each'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2902:in `assign_attributes'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2775:in `attributes='
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/nested_attributes.rb:374:in `assign_to_or_mark_for_destruction'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/nested_attributes.rb:361:in `assign_nested_attributes_for_collection_association'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/nested_attributes.rb:352:in `each'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/nested_attributes.rb:352:in `assign_nested_attributes_for_collection_association'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/nested_attributes.rb:244:in `addresses_attributes='
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2906:in `send'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2906:in `assign_attributes'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2902:in `each'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2902:in `assign_attributes'
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2775:in `attributes='
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.8/lib/active_record/base.rb:2663:in `update_attributes'
    from (irb):7

When I change the Rails version to 2.3.5:

ruby script/console 
Loading development environment (Rails 2.3.5)
>> User.first.update_attributes(:addresses_attributes => {'0' => {:id => '1', :city => 'York', '_delete' => '1'}})
=> true
>> User.first.addresses
=> []