Rails running duplicate queries

My app retrieves a set of tags per post, but for some reason it is running duplicate queries:

Post Load (0.2ms)  SELECT  `posts`.* FROM `posts`  WHERE `posts`.`user_id` = 1                      
Tag Load (0.2ms)  SELECT `tags`.* FROM `tags` INNER JOIN `post_tags` ON `tags`.`id` = `post_tags`.`tag_id` WHERE `post_tags`.`post_id` = 107
Tag Load (0.3ms)  SELECT `tags`.* FROM `tags` INNER JOIN `post_tags` ON `tags`.`id` = `post_tags`.`tag_id` WHERE `post_tags`.`post_id` = 107  ORDER BY post_tags.created_at
Tag Load (0.1ms)  SELECT `tags`.* FROM `tags` INNER JOIN `post_tags` ON `tags`.`id` = `post_tags`.`tag_id` WHERE `post_tags`.`post_id` = 106
Tag Load (0.2ms)  SELECT `tags`.* FROM `tags` INNER JOIN `post_tags` ON `tags`.`id` = `post_tags`.`tag_id` WHERE `post_tags`.`post_id` = 106  ORDER BY post_tags.created_at
Tag Load (0.2ms)  SELECT `tags`.* FROM `tags` INNER JOIN `post_tags` ON `tags`.`id` = `post_tags`.`tag_id` WHERE `post_tags`.`post_id` = 105
Tag Load (0.2ms)  SELECT `tags`.* FROM `tags` INNER JOIN `post_tags` ON `tags`.`id` = `post_tags`.`tag_id` WHERE `post_tags`.`post_id` = 105  ORDER BY post_tags.created_at

to keep it simple my code in the view page:

@posts.each do |post| 
    # code/html to print out post here
    print_tags(post.tags.order('created_at desc'))
end

What I don't understand is why it runs a query first without the order_by, and then runs the query with it. Performance isn't bad yet, but if it really is running two queries for each post, then that could get ugly pretty fast.