"trending" broken?

I was searching for chess articles and in #chess is only one article. But e.g. this article says at the bottom "2 weeks ago by iobates in chess" but the one article on "chess" says "4 weeks ago by crok in games". This is confusing. In which "trending" category does a posting appear? And is there a good site documenation?

PS: now this article is in #chess, too, because if you use a hashtag in your text, it is automatically added to the hashtag line below the article.