HTML tags do not work in archives

Here’s something I noticed in WordPress 1.5-beta-1 2004-12-31. I use various HTML tags in my articles, like strong, code, ul. They look fine when the articles are viewed on the main page of the site. However they vanish when I browse the articles from the archives (by date or by category, for example) or if the articles come from a search query.

Here’s an example:
– on the homepage http://www.macuser.ro/ there is an article with a “code” block and a “strong”-ed word. Currently the article is the third from top to bottom (it’s in Romanian)
– if you click on “December” ( http://www.macuser.ro/2004/12/ ) you’ll see the same article but the tags are absent.

Is this a bug or is something I can fix through a setting?