I took two screenshots which I can’t attach here. I sometimes see topics without a category badge. When I edit the topic (I can because it’s either my own topic or I am TL3 or TL4) I see that the category has been assigned, but the badge is just not being displayed. I am seeing it right now on this very forum.
the badge is missing both on the overview of topics and when I open the topic itself.
I have in the past also see it happen to all badges of a particular category, but most often it happens to one or two topics at the time. I think after an hour or so I have seen the badge show up again.