Dir owner 'nobody' and group 'root' after mounting container volume with `addGroupOwner` set to true.

When running a lambda function component in Greengrass v2.12.2 the mounted volume does not seem to have the correct owner.

For the host dir I have the following owner, group and permissions: drwxr-xr-x root root.

Greengrass is installed with --component-default-user ggc_user:ggc_group which I can confirm in the effective config as posixUser: "ggc_user:ggc_group"

My lambda configuration is as follows

{
  "lambdaFunction": {
    ...
    "componentLambdaParameters": {
      "pinned": true,
      ...
      "linuxProcessParams": {
        ...
        "containerParams": {
          "volumes": [
            {
              "sourcePath": "/host/dir",
              "destinationPath": "/dir",
              "addGroupOwner": true,
              "permission": "rw"
            }
          ]
        }
      }
    }
  }
}

And in my lambda the owner I get is nobody and group is root while the posix permisssions for the mounted directory are drwxr-xr-x.

Also neithrer addGroupOwner nor permission seem to make a difference in my case; it's always drwxr-xr-x nobody root.

(Just in case it is relevant I fetch the owner programmatically in Kotlin/Java with Files.getOwner(path) and group with Files.getAttribute(this, "posix:group", NOFOLLOW_LINKS))

I was expecting the group to be ggc_group and owner to be ggc_user. Am I missing something?

My ultimate goal is to be able to create a file in the mounted volume but I get permission denied not surprisingly.