In FO search with demo data, I search "richesse ametys motfake".
The word "motfake" is not present in any page or documents.
But I have 2 results pages which contain "richesse" and "ametys"

The executed query is full_fr:(+richesse\ +ametys\ +motfake)
In Solr console,

• if I execute this query I have 2 results.
• if I execute this query without espaced character \ full_fr:(+richesse +ametys +motfake), I have no results as excepted

See org.ametys.web.frontoffice.SearchGenerator.addAllWordsTextFieldQuery(Collection<Query>, String, Request)