That’s exactly one of the problems I wanted to address with this new feature. The semantic search will always find something.
At the moment, the semantic search is pretty barebones. It consists of just a few lines of code in the backend and returns whatever is closest semantically. It lacks any of the search features we added to the standard search over the last decade, like Search Improvements in 2.3 and many others. Because of this, it’s currently being offered as a complementary results set.
If the feature is well-received and we can perfect the UI in the product, then we’ll attempt to incorporate the Discourse specific parts to the semantic search results.