I checked on my own system, and I started getting the same error too. I think the changes made in the latest updates caused this. It seems the changes made to the discourse-ai system are preventing manual edits. I was able to perform these actions yesterday, but after today’s updates, I can no longer do so.
https://github.com/discourse/discourse/commit/d5173c62b534f0cd7ee1bc547d7ef3e97a811d6f
For your information @nat