Announcements never show up in active topics list in a category

When a category has active topics enabled, regular topics and sticky topics can be shown there, but (non-global) announcements (from this a category's subforum) never do.

Whenever a regular topic is displayer in category's active topics list, switching this topic to 'announcement' removes it from active topics list. Switching it back to 'normal topic' returns it back to the active topic list.