magento 2.3.2 with elasticsearch 6.8.2 returns results only present in mysql search_query table

Question

Prerequisites: installing and configuring Elasticsearch 6.8.2 in a magento 2.3.2 installation as per devdocs (reindexing and cache:clean ok)

Step to reproduce: inserting a term in magento frontend search bar

Expected behaviour: have back suggestions from elastic docs

Actual result: we see that the autocomplete suggestions (returned via ajax) in the magento search-bar still return terms present in mysql search_query table (popular search terms inserted by previous visitors). These terms are not present in elastic (checked via Kibana Dev Tools).

So far we didn't dig in the inner of the core Magento 2.3 elastic module but this points us to the conclusion that the search results are still coming from mysql and not from elastic.

that leads us to 2 questions:

1. is that a bug? is the magento2.3 elaticsearch module still querying the mysql search_query table?

2. the second, more generic and perhaps due to the fact we are not seasoned ekl stack users: is there a simple way to know if search results come from mysql or from elastic? are we supposed to use xdebug or does elastic come with tools that help us understand if a GET call has been made (perhaps using Kibana)?

elastic error logs does not show errors, elasticsearch_access.log is empty.

thanks, romeo

Magento 2.3.2 Elasticserch 6.8.2 Kibana php7.2

kibana query that returns empty result: "query": { "bool": { "must": [ { "query_string": { "query": "mySearchedTerm", "analyze_wildcard": true, "default_field": "*" } } ], "filter": [], "should": [], "must_not": [] } },