Autocomplete path doesn't recognized nested field

[Andrea_Luconi]

I use mongo DB Atlas with autocomplete.
It works fine if in the json configuration I insert fields that are not nested:

{
  "mappings": {
    "dynamic": false,
    "fields": {
      "model": [
        {
          "foldDiacritics": false,
          "maxGrams": 10,
          "minGrams": 4,
          "type": "autocomplete"
        }
      ],
      "title": [
        {
          "foldDiacritics": false,
          "maxGrams": 10,
          "minGrams": 3,
          "type": "autocomplete"
        }
      ]
    }
  }
}

But in my DB I have a nested object “optional.hash” and according to the doc I should do something like that:

{
  "mappings": {
    "dynamic": false,
    "fields": {
      "optional.hash": [
        {
          "foldDiacritics": false,
          "maxGrams": 10,
          "minGrams": 3,
          "type": "autocomplete"
        }
      ],
      "model": [
        {
          "foldDiacritics": false,
          "maxGrams": 10,
          "minGrams": 4,
          "type": "autocomplete"
        }
      ],
      "title": [
        {
          "foldDiacritics": false,
          "maxGrams": 10,
          "minGrams": 3,
          "type": "autocomplete"
        }
      ]
    }
  }
}

Then the aggregation pipeline is:

[
    {
      $search: {
        compound: {
          should: [
            {
              autocomplete: {
                query: `${query}`,
                path: 'model',
                fuzzy: {
                  maxEdits: 2,
                  prefixLength: 3,
                  maxExpansions: 256,
                },
              },
            },
            {
              autocomplete: {
                query: `${query}`,
                path: 'title',
                tokenOrder: 'sequential',
                fuzzy: {
                  maxEdits: 1,
                  prefixLength: 1,
                  maxExpansions: 256,
                },
              },
            },
            {
              autocomplete: {
                query: `${query}`,
                path: 'optional.hash',
                tokenOrder: 'sequential',
              },
            },
          ],
          minimumShouldMatch: 1,
        },
      },
    },

And it has always worked but not anymore. I had to make sure that the value for the autocomplete is not nested in an object and so it works.
Anyone else have the same problem as me?

[Andrea_Luconi]

In mongo atlas, in “mappings”, I define the nested field like this:

"optional": {
    "fields": {
        "hash": {
            "foldDiacritics": false,
            "maxGrams": 10,
            "minGrams": 3,
            "type": "autocomplete"
         }
    },
    "type": "document"
 }