It worked! I was able to reproduce it removing only the embedding field but keeping the non indexed fields in the document. Here's the schema:

{
  "name": "test",
  "fields": [
    {
      "name": "updated",
      "type": "int64",
      "facet": false,
      "optional": false,
      "index": true,
      "sort": true,
      "infix": false,
      "locale": "",
      "stem": false,
      "store": true
    },
    {
      "name": "externalStatusCode",
      "type": "string",
      "facet": false,
      "optional": false,
      "index": true,
      "sort": false,
      "infix": false,
      "locale": "",
      "stem": false,
      "store": true
    },
    {
      "name": "projectBudgetWithoutTaxes",
      "type": "float",
      "facet": false,
      "optional": false,
      "index": true,
      "sort": true,
      "infix": false,
      "locale": "",
      "stem": false,
      "store": true
    },
    {
      "name": "locationNutsCode",
      "type": "string",
      "facet": false,
      "optional": true,
      "index": true,
      "sort": true,
      "infix": false,
      "locale": "",
      "stem": false,
      "store": true
    },
    {
      "name": "externalReference",
      "type": "string",
      "facet": false,
      "optional": true,
      "index": true,
      "sort": false,
      "infix": false,
      "locale": "es",
      "stem": false,
      "store": true
    },
    {
      "name": "title",
      "type": "string",
      "facet": false,
      "optional": true,
      "index": true,
      "sort": true,
      "infix": false,
      "locale": "es",
      "stem": false,
      "store": true
    }
  ],
  "default_sorting_field": "",
  "enable_nested_fields": false,
  "symbols_to_index": [],
  "token_separators": []

} `````` I'll upload the file in the next message