I was interested if it’s the reply or the fact that you are watching the topic which is responsible for the notification. That’s why I asked if you are also notified if you change the topic tracking status to watching but do not reply.
I think I was able to reproduce this without the reply. My steps to reproduce were:
- Create 2 topics as a test user (Topic A & Topic B)
- As the admin/moderator, visit topic A and change the topic tracking status to “watching”
- Visit topic B, select the post, and merge it into topic A
Edit:
It’s important that you merge the first post of topic B into topic A. Don’t move only replies.