Why is EMQX greengrass component ignoring custom configuration?

I am deploying a bunch of components, which depend on the EMQX (they specify it as dependency). And then I am deploying the EMQX. I have to explicitly define it in the deployment because I need to apply custom configuration for it. However when the component is deployed, this configuration is completely ignored and the component is instead deployed with just the default configuration. Here is the component config in the deployment:

    "targetArn": "arn:aws:iot:eu-west-1:123456789:thinggroup/development-dev-123456v2",
    "revisionId": "705",
    "deploymentId": "68ef313e-5516-4ea9-9f29-c48ac52e1d34",
    "deploymentStatus": "ACTIVE",
    "iotJobId": "85ce3105-1a45-461f-a9d7-d677c1d95aa3",
    "iotJobArn": "arn:aws:iot:eu-west-1:123456789:job/85ce3105-1a45-461f-a9d7-d677c1d95aa3",
    "components": {
        "aws.greengrass.clientdevices.mqtt.EMQX": {
            "componentVersion": "2.0.1",
            "configurationUpdate": {
                "merge": "{\"emqxConfig\":{\"listeners\":{\"ssl\":{\"default\":{\"enabled\":false}},\"tcp\":{\"default\":{\"enabled\":true,\"bind\":1883}}},\"authorization\":{\"no_match\":\"allow\"}},\"dockerOptions\":\"-p 1883:1883 -l com.company.cic.srv -l com.docker.service=emqx\",\"authMode\":\"bypass\"}",
                "reset": [
                    ""
                ]
            }
        },
...

The intention is to have the EMQX as local broker. Can someone plz explain what's going on here? There is nothing in the logs about the deployment, so I cannot troubleshoot this.