Browsing the forum via Latest, I noticed that some threads, specifically the review threads of Mike, Robin and Victor, do not show the category they are posted in.
I just looked at the same threads in Latest, and those threads do show the category, so sounds like a potentially local issue?
Couple things to try: (usual stuff) restart the browser and reload the forum page, also maybe try switching your theme from Dark to another one and back and see if that might reload the settings and fix it.
(I verified I can see categories on those topics in both the Dark and zeronoise themes.)
This was weird, I’ve had the issue since I noticed it two days ago, but now it shows just like it should, without me having done anything about it. I’m hereby suspecting the solution was you changing themes.