Yeah the results are Post level. Not Topic level. And indeed it may suppress multiple entries per single Topic.
If your search criteria includes a specific Topic, though, it will show multiple entries potentially for that Topic.
It will return posts from a single Topic with the addition of the right parameter, e.g.:
https://meta.discourse.org/search?q=result%20topic%3A202121%20order%3Alatest
https://meta.discourse.org/search?q=result%20topic%3A202121%20order%3Alatest