Counter_cache not updating

Hi

I’m using those 2 models:

class Topic < ActiveRecord::Base
has_many :articles, :order => :rank
end

class Article < ActiveRecord::Base
belongs_to :topic, :counter_cache => true
end

The “counter_cache” column in the “topics” table does increase when
adding a new article, but it does not update when updating article’s
topic or when deleting the article.

Any idea ?