confused about dates in this discussion forum


I have several posts here and I’m watching if there are new replies. So I go to the first page of discussion and tuesday ( which was the 22 th ) I saw new post. So yesterday.
Now I go to the discussion today and I can only see the last dates would be from 20 th of december. But there are definetely post from 25 th. I received message from Vladka.
What goes wrong with the display of the newly dates of post on your website ?