Notification is created by a job. If the job is evaluated before changes are committed to a database, a notification will have an incorrect URL.
Therefore, the job should be lodged in enqueue_jobs method which is triggered after the transaction:
```ruby
Topic.transaction do
move_posts_to topic
end
add_allowed_users(participants) if participants.present? && @move_to_pm
enqueue_jobs(topic)
```
I improved a little bit specs to ensure that the destination topic_id is set. However, that tests are passing even without code improvements. I couldn't find an easy way to "delay" database transaction.
Meta: https://meta.discourse.org/t/bug-with-notifications-for-moved-posts/168937
e4d51e5b0a