Threads stop showing similar threads widget after they are merged

invalid@example.com (Mr Lucky), Mr Lucky
Sun, 01 Jun 2025 09:22:14 +0000
Enhanced Search support

I had four threads all about the exact same topic with the same keywords in the title. They all appeared in a similar threads widget which I believe is mostly (or 100%?) based on thread title . Each of these threads showed the other similar threads in the widget, as you would expect.

So I decided to merge them all as they really were similar.

To start with I merged two of them but found that although the thread that was merged into still showed in the similar threads widget for the...