Categories not showing after import

I have created an XML import file. It imports 72 categories and 72 posts (1 post in each category). The import works perfectly, but when I go look at the Categories that I imported, they don’t show. Here’s the kicker. The paging shows. In other words, before the import, there is only a single page of categories. After the import, there are 5 pages (because there are 72 new categories); however, as I page through pages 2-5, the list is empty on each page. If I go look at the posts, I can view them and see that they are assigned to the right category. In fact, when editing a post, the category list is perfectly correct. It’s just when I go to the Categories section that they aren’t showing. Now get this. If I make any change to the site at all (e.g. update a post, update a page, update a category that I can see, etc.), then they all appear!. Is there some sort of refresh function that needs to run? Could it be a problem with my XML file?