[BUG] Azure.Search.Documents performs vector search successfully, but results are "null"

[rossmodolin]

Library name and version

Azure.Search.Documents 11.5.1

Describe the bug

We are implementing a search service using vectorized queries with filter in which the only field that is searchable is the one that contains the text embedding. We are able to receive a response for the request, but all the properties return as "null". All the data we need is present in the Non-public members' properties, but they are not retrievable through the GetResultsAsync() method.

Expected behavior

The method GetResultsAsync() should be able to correctly map the raw response content to the properties of the class.

Actual behavior

All properties return as "null", as shown in the image below:

Reproduction Steps

public class AzureSearchDocument
{
    public string Id { get; set; }

    public string Title { get; set; }

    public string Product { get; set; }

    public ReadOnlyMemory<float> TextEmbedding { get; set; }
}

class Program
{
    static Task Main(string[] args)
    {
        GetSearchResultsAsync(6, "ProductName", questionEmbedding);
    }

    public static async Task GetSearchResultsAsync(int maxResults, string product, ReadOnlyMemory<float> questionEmbedding)
    {

        SearchClient searchClient = new(new Uri("replace with url"), "index-search", new AzureKeyCredential("key"));

        SearchResults<AzureSearchDocument> response = await searchClient.SearchAsync<AzureSearchDocument>(
            new SearchOptions
            {
                VectorSearch = new()
                {
                    Queries = { new VectorizedQuery(questionEmbedding) { KNearestNeighborsCount = maxResults, Fields = { "textEmbedding" } } }
                },
                Filter = $"product eq '{product}'"
            });

        int count = 0;
        await foreach (SearchResult<AzureSearchDocument> result in response.GetResultsAsync())
        {
            count++;
            AzureSearchDocument doc = result.Document;
            Console.WriteLine($"[AzureSearchDocument] {doc.Id}: {doc.Title}");
        }
        Console.WriteLine($"Total number of search results:{count}");

    }
}

Here is the configuration of the Index:

Environment

• .NET SDK:
  Version: 8.0.101
  Commit: 6eceda187b
  Workload version: 8.0.100-manifests.825c015e

• Runtime Environment:
  OS Name: Windows
  OS Version: 10.0.19045
  OS Platform: Windows
  RID: win-x64

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