The recent redesign has changed the category structure. “Bug” is now a subcategory. Links to categories that were moved no longer work. This affects not only topics here in the forum, but also, for example, on GitHub and any other sites that might link here. That is one of the downsides of such a restructuring.
Permalinks for automatic redirection, regardless of where these categories are linked, would likely be helpful. Ideally, the software would generate these automatically when a category becomes a subcategory.