The bad choice:
I was experimenting on a category’s description topic, and tried “Make Private Message” on it.
Tried to revert/fix
Then I chose “Make Public Topic”.
The category showed the right description in the category list, but the category description topic no longer appeared inside the category.
Then I found the topic in the Uncategorized category, but changing the category (via full edit or name edit) never changed it out of Uncategorized.
My real fix:
I traced through the github, and found that convert_to_private_message changes the topic.archetype and nils the topic.category_id. In this stubborn category description topic, sql showed archetype ‘regular’ and category_id of null. Something was preventing a change to the category_id. I changed that topic record to the right category_id, and everything looks good again. The category description is correct, and the category description topic is back and public in the right category.
I’m 2 days into my first ever Discourse install, which may explain how I goofed it up making strange UI choices. Discourse is really great, and I thought it might be helpful to share the only strange experience I’ve had so far.