ok, so i have tested now and I get it to work sort of. my schemas has these fields. and when using facet_by: attributes.string_value and facet_return_parent: “attributes.string_value” it is not possible for me to only get the facets for the traits that have a specific trait_type.

{
      "name": "attributes",
      "type": "object[]",
      "optional": true
    },
    {
      "name": "attributes.trait_type",
      "type": "string[]",
      "facet": true
    },
    {
      "name": "attributes.string_value",
      "type": "string[]",
      "facet": true,
      "optional": true
    }