metafields identifiers return null except for one

[Lederer]

This query does only return one metafield with value, but all of them should be set (API 2023-04):

products(first: $first, after: $after, query:$productType) {
                    edges {
                        node {
                            id
                            title
                            metafields(identifiers: [ 
                                { namespace: "custom", key: "sound_file" }, 
                                { namespace: "custom", key: "sample_json" }, 
                                { namespace: "custom", key: "sound_example" }
                            ]) {
                                type
                                key
                                value
                            }
                        }
                    }
                }
            }

There are definitely values for all of them:

But it return only one:

{
    node: {
      id: 'gid://shopify/Product/8419937681723',
      title: 'Classic Star - Tom Set',
      metafields: [
            null,
            null,
            {
                  type: 'single_line_text_field',
                  key: 'sound_example',
                  value: "['TAMA_Toms.wav', 'TAMA_Full_Kit.wav']"
            }
       ]
    }
  }

Is there a bug in the API?

[Lederer]

I got it, I forgot to check this box here: