Well, it's inconsistent because the distance returned is not the same.

See this commit where Yoann had to tweak the test so that it works with Lucene and Elasticsearch: https://github.com/hibernate/hibernate-search/pull/1136/commits/9f76628900a65162630b2d00adef95ac34e7517e

Personally, I find Elasticsearch behavior more correct and I'm for improving the consistency between both backends.