I had a user with this exact same problem. Here’s the solution I gave her.
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If you had accidentally “ Muted ” the topic (blue bar, bottom left after the last post), "You will never be notified of anything on this topic, and it will not appear on latest ".
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She checked and she did indeed “Mute” the topic. Once she clicked on it again and refreshed the page, the topic showed in Latest for her.
You can also impersonate this user, go to their preferences, then categories, then scroll down to mute and click on search to see if the topic is muted. Just a thought.