Symfony Elasticsearch Integration (FOSElasticaBundle)

Question

I am busy implementing elasticsearch for a customer project. Elasticsearch seems pretty powerful and has a neat API.

Integrated with FOSElasticaBundle i have the following configuration:

fos_elastica:
clients:
    default:
        host: localhost
        port: 9200
indexes:
    app:
        client: default
        settings:
            index:
                analysis:
                    filter:
                        synonym:
                            type: synonym
                            synonyms: ["katze, katz"]
                    analyzer:
                        synonyms:
                            tokenizer: standard
                            filter: [ lowercase, synonym ]

        types:
            article:
                mappings:
                    name: { analyzer: synonyms }
                    shortDescription: ~
                    description: ~
                    categories:
                        type: "nested"
                        properties:
                            name: ~
                persistence:
                    driver: orm
                    model: ShopBundle\Entity\Catalog\Article
                    provider: ~
                    finder: ~
                    listener: ~

When i search for "Katze" (German for cat), i get the expected results (Articles having the string "Katze" in its name. When i search for "Katz", i get 0 results.

This is a simpler configuration then i really use. I tried it with nGram tokenizer and other custom analyzers... I don't get rid of the feeling that elastic isn't indexing the field with analyzed content.

When i use the "_analyze" API endpoint, and i send a string and the analyzer name (one of my custom analyzers), the result (list of tokens) looks right!

Do i miss something?

Version of FOSElastica is 4.0.1 and elasticsearch server 5.6.3.