https://www.elastic.co/guide/en/elasticsearch/reference/current/breaking-changes-6.0.html :

The auto_generate_phrase_queries parameter for the query_string query has been removed, use an explicit quoted query instead. If provided, it will be ignored and issue a deprecation warning.

We should first remove it from the code since it's ineffective. We then figure out if we need to find alternatives.
This option was mostly used to improve precision in case of acronyms searches or words with dash.

A query like N.A.S.A missions with auto_generate_phrase_queries is using a filter like "N.A.S.A" missions without this option we are running
N A S A missions.

Finding ideal solutions is out of the scope of this ticket another task need to be created for this.