Timestamps with has_and_belongs_to_many

I'm using Rails 2.3.5.

All of my tables include the default timestamps (created_at and updated_at) including my join tables for has_and_belongs_to_many (habtm) associations. When I retrieve the habtm objects using the convention task.colors, Rails returns the timestamps from the join table instead of the color table. Since it returns Color objects, the timestamps should be from the colors table since that reflects when the Color object was last updated.

Both tables have timestamps, is Rails confusing the two? Or is this by design?

class Task < ActiveRecord::Base
  has_and_belongs_to_many :colors
end

class CreateColorsTasks < ActiveRecord::Migration
  def self.up
    create_table :colors_tasks, :id => false do |t|
      t.integer 'color_id', :null => false
      t.integer 'task_id', :null => false
      t.timestamps

class CreateTasks < ActiveRecord::Migration
  def self.up
    create_table :tasks do |t|
      t.string 'name'
      t.timestamps

class CreateColors < ActiveRecord::Migration
  def self.up
    create_table :colors do |t|
      t.string 'name'
      t.timestamps