port in parse-dashboard config.json doesn't work

Enviroment: parse-dashboard 5.0.0 / parse-server 6.0.0
The port in --config dashboard.json doesn't work, the only way to work is give a particular port with --port:

parse-dashboard --config dashboard.json  --port 8080

dashboard.json

{
        "apps": [{
                "serverURL": "https://server.com/parse",
                "appId": "parseserver",
                "masterKey": "keykey",
                "allowInsecureHTTP": "true",
                "port": 8080,
                "appName": "BaaS Adhoc"
        }]
}

I am not sure port should be place into the root or apps in dashboard.json, but it doesn't works as I have tried both.

Originally posted by @fdddf in https://github.com/parse-community/parse-dashboard/issues/2113#issuecomment-1521438890

Reproduce the issue with parse-dashboard --config dashboard.json, testing the shown port placement in both the root and apps object. Trace how dashboard.json is loaded and how the CLI resolves the port; done means the configured port is used without requiring --port.