When posts are moved from one topic to another, the `topic_user.bookmarked` column for all users in the new and the old topic needs to be resynced, for example because a user bookmarks post 12 in topic 1, then it is moved to topic 2, the topic_user record for topic 1 should no longer be bookmarked. A background job has been added to sync the column for a specified topic, or for no topic at all, which does it for all topics like the migration.
Also includes a migration that we have run in the past to fix bad data.
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This has been addressed in other places in the past:
https://github.com/discourse/discourse/pull/10211https://github.com/discourse/discourse/pull/10188
Martin Brennan