Double Categories

I really love the theme The Newswire, but since an upgrade some time ago there is something wrong with categories. Almost all my blog items have the category ‘News’. But sometimes a blog item should have more than one category, for instance ‘News’ and ‘Video’. All the other blog items on the homepage immediately get both of these categories. They are always adopting the category or categories of the last blog item. I found a way around this problem by posting a private message with the category ‘News’ immediately after a double category-blog. The private item will not be visible on the homepage, but all the categories are ok again (because the private-item was the last one I posted). But there must be another way to fix this problem, I suppose!

The page I need help with: [log in to see the link]