Display all items pager not working with ES

Problem

Elasticsearch connector based view doesn't display all results when pager is set to Display all items

I've an elasticsearch server (v6.7.2) and a fresh drupal 8 install:

1. Enable elasticsearch_connector and search_api modules
2. Create an elasticsearch cluster and set it to the elsaticsearch server.
3. Generate 50 content with devel_generate
4. Add a index to index article content type, add nid as field
5. Create a view based on indexed articles and display nid as rows field
6. Change pager from default 'paged output, mini pager' to 'display all items, no offset'

Result: only the 10 first items are shown. Any ideas on this strange behavior?

Thank you in advance