[QUERY]Why is ChatMessageContext.Citations ChunkId field is empty after calling completion.GetMessageContext()

[aorlenko]

Library name and version

Azure.AI.OpenAI

Query/Question

I'm using Azure.AI.OpenAI library version 2.1.0 and data source as Azure search index with chunked data.
When I'm getting results back after calling to CompleteChatAsync, I need to have access to all Citations and their ChunkId properties.

The code I'm using:

            var azureClient = new AzureOpenAIClient(
                new Uri(gptUrl),
                new System.ClientModel.ApiKeyCredential(gptKey),
                new AzureOpenAIClientOptions()
                {
                    NetworkTimeout = TimeSpan.FromSeconds(30),
                });

            ChatClient chatClient = azureClient.GetChatClient(gptName);

            var completionOptions = new ChatCompletionOptions()
            {
            };

                var azureSearchDataSource = new AzureSearchChatDataSource()
                {
                    InScope = false,
                    QueryType = DataSourceQueryType.Simple,
                    FieldMappings = new DataSourceFieldMappings(),
                    Endpoint = new Uri(_appSettings.SearchServiceEndpoint),
                    IndexName = xxx,
                    Authentication = DataSourceAuthentication.FromApiKey(_appSettings.SearchServiceKey),
                    TopNDocuments = _appSettings.AzureSearchTopNDocuments
                };

                azureSearchDataSource.FieldMappings.ContentFieldNames.Add("content");
                azureSearchDataSource.FieldMappings.ContentFieldNames.Add("date");
                azureSearchDataSource.FieldMappings.TitleFieldName = "title";
                azureSearchDataSource.FieldMappings.FilePathFieldName = "url";
                azureSearchDataSource.FieldMappings.UrlFieldName = "externalUrl";

                completionOptions.AddDataSource(azureSearchDataSource);

                ChatCompletion completion = await chatClient.CompleteChatAsync(
                [
                new SystemChatMessage(systemMessage),
                ..contextMessages,
                new UserChatMessage(userMessage),
                ], completionOptions);

                var messageContext = completion.GetMessageContext();

All works and citations are retrieved, but the messageContext Citations objects always have ChunkId="0".
Though in my Azure search index, there are always chunk_id values populated.
Are there any additional steps or setup I need to do, in order to get ChunkId values back?
Thanks.

Environment

.NET 8

Hosting: Azure App Service on Windows.

Packages:

[github-actions]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @jpalvarezl @ralph-msft @trrwilson.