Login module control flag is not available in JAAS, using docker environment

Question

I try to deploy Scala-based KafkaClient inside a docker compose network. Problem is that if I hardcode JAAS-config in application.conf like this:

  client-config {
    bootstrap.servers = ${bootstrap.servers}
    schema.registry.url = ${schema.registry.url}
    security.protocol=SASL_PLAINTEXT
    sasl.mechanism = "PLAIN"
    sasl.jaas.config = """
        org.apache.kafka.common.security.plain.PlainLoginModule required
        username = 'kafka'
        password = 'pwd';
        """
  }

It works correctly. But if I use 'include' inside application.conf like this:

include "/opt/kafka_creds/jaas.conf"

jaas.conf:

JAAS_CONF = """
        org.apache.kafka.common.security.plain.PlainLoginModule required
        username = 'kafka'
        password = 'pwd';
        """

I've got this kind of error:

Caused by: java.lang.IllegalArgumentException: Login module control flag is not available in the JAAS config

I also tried to add jaas configuration via environment, but it didn't work. My docker-compose.yml looks like:

version: '3'
services:
  service_name:
    image: adoptopenjdk/openjdk11:latest
    hostname: service_name
    container_name: service_name
    volumes:
      - ./build/distributions-fat/app-0.1.jar:/app-0.1.jar
      - ./projects/:/opt/projects/
      - /opt/kafka_creds/kafka_client_jaas.conf:/opt/kafka_client_jaas.conf
      - /opt/kafka_creds/jaas.conf:/opt/kafka_creds/jaas.conf
    networks:
      - network_name
    command: ["java", "-jar", "-Djava.security.auth.login.config=KafkaClient:/opt/kafka_client_jaas.conf", "app-0.1.jar"]

networks:
  network_name:
    name: network_name