I've just noticed that on the most recent topic challenge, Writing challenge: Rise to Power - 30 July 2019 - 17 August 2019, there's a link at the bottom to my initial post from 2+ years ago about starting this whole thing. In fact, the end section of the post appears to be directly copy-pasted from one of my original posts on the matter (right down to my user ID in the link). Cool.
The problem is, this includes a link with the old URL - "writers" instead of "writing". The exact URL linked is
https://writers.meta.stackexchange.com/q/1275/13002. This means that the post isn't showing up as "linked" in the sidebar:
This seems like a bug - the questions should show up as linked even if it's using the old URL.