Unity Addressables InstantiateAsync prefab mesh is not visible in Build

I am instantiating a simple Prefab with a simple mesh (small plane) in a scene. The Instantiation is performed by a proxy object, after instantiation it sets properties on the newly created instance and removes itself.

This all works fine when running the scene in the editor, each instance is created and appears and can be seen, however if I make a packaged build of the game, the instantiation happens (I checked via breakpointing the instantiation code) but the mesh isn’t visible in the scene.

The Addressables groups have been built, I am seeing no invalid key exceptions, and it works as intended in editor. The mesh is from an FBX file which isn’t in any addressables group.

Is there something I am missing? The code attached to the proxy objects is as follows (you can see I have tried using both GUID and Address to reference the prefab from addressables.

Thanks in advance

   public AssetReference asset;

   public string assetAddress;
        
    protected void Awake()
    {
        AsyncOperationHandle h = Addressables.InstantiateAsync(assetAddress, gameObject.transform.position, gameObject.transform.rotation);
        //AsyncOperationHandle h = asset.InstantiateAsync(gameObject.transform.position, gameObject.transform.rotation);
        h.Completed += (AsyncOperationHandle obj) =>
        {
            if (obj.Status == AsyncOperationStatus.Succeeded)
            {
                GameObject thing = (GameObject) obj.Result;
                thing.transform.localScale = gameObject.transform.localScale;

                Destroy(gameObject);
            }
            else
                Debug.LogError("Failed in instatiate asset " + assetAddress);
        };
    }```