.Net: Net: Bug: 'd' is an invalid start of a value. LineNumber: 0 | BytePositionInLine: 0.

[jeffrey55wu]

Describe the bug
Intermittently, calling AzureOpenAlChatCompletion.GetChatMessageContentAsync(...) throws a System.Text.Json.JsonReaderException with the message: "'d' is an invalid start of a value. LineNumber: 0 | BytePositionInLine: 0." The exception appears to originate from OpenAl.Chat.ChatCompletion.FromResponse (OpenAl.Chat.ChatCompletion.op_Explicit), suggesting the SDK is attempting to parse a non-JSON response body.
This happens sporadically in production (roughly once or twice per day) even when sending the same normalized transcript. Most calls succeed; some fail with the above exception.

To Reproduce
Note: This is intermittent and hard to reproduce deterministically.

1. Initialize Semantic Kernel with Azure OpenAl chat completion.
2. Prepare a normalized transcript and a simple "summarize" prompt.
3. Call GetChatMessageContentAsync with non-streaming settings.
4. Observe occasional JsonReaderException parsing the response.

Expected behavior
The call should return a summary string (ChatMessageContent) consistently. No JsonReaderException should be thrown, and the SDK should handle or surface non-JSON responses gracefully.

Screenshots
N/A

Platform

• Language: C#
• Source: <PackageReference Include="Microsoft.SemanticKernel" Version="1.65.0" />
• Al model: OpenAl:GPT-40-mini (2024-07-18)
• SDK version: dotnet8.0.19:0tel1.8.1:ext1.3.0-d
• Connector: Azure OpenAl Chat Completion

Additional context
Frequency: Intermittent; typically 1-2 occurrences per day under production load.
Input: A normalized transcript (string) used for summarization. The same input can succeed or fail unpredictably.

Workarounds tried
Retrying the failed call usually succeeds on subsequent attempts, which further suggests a transient service or transport response issue rather than input-related formatting.
Ensuring non-streaming settings (no explicit stream flags set) and basic prompt formatting did not resolve the intermittent failures.