Filebeat running in docker not creating ECS field `host.name`

I am running a filebeat 7.14.1 in a docker container on a debian host. I am using the modules mysql and system. The filbeat is sending the documents directly to elasticsearch, those are my ingest nodes with the according piplines belonging to the filebeat modules

I excpeted that the ECS field host.name would be created, but it is missing. This lead also into the fact that they are not respected in the kibana security integration on page /app/security/hosts/allHosts? cause the requests there are based on the field presence of host.name.

All components are in version 7.14.1.

Configuration can be find here:

Does anyone hava a idea? I can not find a related issue for that.

Thx