.NET: DevUI is not supporting testing workflow which is having a sub-workflow

Please see the example of my implementation below.

private static void Main(string[] args)
{
var builder = WebApplication.CreateBuilder(args);

// Set up the Azure OpenAI client
var endpoint = builder.Configuration["AZURE_OPENAI_ENDPOINT"] ?? throw new InvalidOperationException("AZURE_OPENAI_ENDPOINT is not set.");
var deploymentName = builder.Configuration["AZURE_OPENAI_DEPLOYMENT_NAME"] ?? "gpt-4o-mini";

var chatClient = new AzureOpenAIClient(new Uri(endpoint), new AzureCliCredential())
.GetChatClient(deploymentName)
.AsIChatClient();

builder.Services.AddChatClient(chatClient);

// Define some example tools
[Description("Get the weather for a given location.")]
static string GetWeather([Description("The location to get the weather for.")] string location)
=> $"The weather in {location} is cloudy with a high of 15°C.";

[Description("Calculate the sum of two numbers.")]
static double Add([Description("The first number.")] double a, [Description("The second number.")] double b)
=> a + b;

[Description("Get the current time.")]
static string GetCurrentTime()
=> DateTime.Now.ToString("HH:mm:ss");

// Register sample agents with tools
builder.AddAIAgent("assistant", "You are a helpful assistant. Answer questions concisely and accurately.")
.WithAITools(
AIFunctionFactory.Create(GetWeather, name: "get_weather"),
AIFunctionFactory.Create(GetCurrentTime, name: "get_current_time")
);

builder.AddAIAgent("poet", "You are a creative poet. Respond to all requests with beautiful poetry.");

builder.AddAIAgent("coder", "You are an expert programmer. Help users with coding questions and provide code examples.")
.WithAITool(AIFunctionFactory.Create(Add, name: "add"));

// Register sample workflows
var assistantBuilder = builder.AddAIAgent("workflow-assistant", "You are a helpful assistant in a workflow.");
var reviewerBuilder = builder.AddAIAgent("workflow-reviewer", "You are a reviewer. Review and critique the previous response.");
builder.AddWorkflow("review-workflow", (sp, key) =>
{
var agents = new List() { assistantBuilder, reviewerBuilder }.Select(ab => sp.GetRequiredKeyedService(ab.Name));
return AgentWorkflowBuilder.BuildSequential(workflowName: key, agents: agents);
}).AddAsAIAgent();

builder.AddWorkflow("TestSubWorkflow", (sp, key) =>
{
UppercaseExecutor uppercase = new();
ReverseExecutor reverse = new();
AppendSuffixExecutor append = new(" [PROCESSED]");

var subWorkflow = new WorkflowBuilder(uppercase)
.AddEdge(uppercase, reverse)
.AddEdge(reverse, append)
.WithOutputFrom(append)
.Build();

// Step 2: Configure the sub-workflow as an executor for use in the parent workflow
ExecutorBinding subWorkflowExecutor = subWorkflow.BindAsExecutor("TextProcessingSubWorkflow");

// Step 3: Build a main workflow that uses the sub-workflow as an executor
Console.WriteLine("Building main workflow that uses the sub-workflow as an executor...\n");

PrefixExecutor prefix = new("INPUT: ");
PostProcessExecutor postProcess = new();

return new WorkflowBuilder(prefix)
.WithName("TestSubWorkflow")
.AddEdge(prefix, subWorkflowExecutor)
.AddEdge(subWorkflowExecutor, postProcess)
.WithOutputFrom(postProcess)
.Build();
}).AddAsAIAgent();

builder.Services.AddOpenAIResponses();
builder.Services.AddOpenAIConversations();

var app = builder.Build();

app.MapOpenAIResponses();
app.MapOpenAIConversations();

if (builder.Environment.IsDevelopment())
{
app.MapDevUI();
}

Console.WriteLine("DevUI is available at: https://localhost:50516/devui");
Console.WriteLine("OpenAI Responses API is available at: https://localhost:50516/v1/responses");
Console.WriteLine("Press Ctrl+C to stop the server.");

app.Run();
}

From DevUI as soon as I try to test the TestSubWorkflow, the DevUI screen freezes itself and it does not execute the sub workflow. The execution from DevUI works fine if I remove the sub workflow.
Also, the workflow with sub workflow can also be tested outside DevUI which is also working fine. It just that the sub-workflow execution is not happening while in DevUI.