.Net: Bug: ConcurrentOrchestration collects responses sequentially from all agents

[anniruddh]

Describe the bug
Creating multiple AzureAIAgents and running tasks concurrently via SK ConcurrentOrchestration does not execute agent task parallel. All agent output is consistently collected in deterministic sequential order. Code sample shared at Step01a_ConcurrentWithStructuredOutput used as reference usage code.

To Reproduce
Steps to reproduce the behavior:

1. Create multiple (e.g. 8) chat response AzureAIAgents via SK PersistenAgentsClient.CreateAgentAsync()
2. Instantiate ConcurrentOrchestration passing in agents created in 1.
3. Start InProcess runtime.
4. Call orchestration.InvokeAsync() with input message.
5. Call and wait for orchestrationResults.GetValueAsync to finish result collection.
6. Observe logs and execution latency.

Screenshots
If applicable, add screenshots to help explain your problem.

Platform

• Language: C#
• Source: nuget: Microsoft.SemanticKernel.Agents.Orchestration Version: 1.60.0-preview
• AI model: gpt-4.1-mini
• IDE: Visual Studio 2022
• OS: Windows

Additional context
Here is a sample log from execution:

info: Logger[0]
REGISTER ACTOR ConcurrentOrchestration RESULTS: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Results
info: Logger[0]
REGISTER ACTOR ConcurrentOrchestration MEMBER #1: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Agent_1
info: Logger[0]
REGISTER ACTOR ConcurrentOrchestration MEMBER #2: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Agent_2
info: Logger[0]
REGISTER ACTOR ConcurrentOrchestration MEMBER #3: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Agent_3
info: Logger[0]
REGISTER ACTOR ConcurrentOrchestration MEMBER #4: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Agent_4
info: Logger[0]
REGISTER ACTOR ConcurrentOrchestration MEMBER #5: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Agent_5
info: Logger[0]
REGISTER ACTOR ConcurrentOrchestration MEMBER #6: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Agent_6
info: Logger[0]
REGISTER ACTOR ConcurrentOrchestration MEMBER #7: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Agent_7
info: Logger[0]
REGISTER ACTOR ConcurrentOrchestration MEMBER #8: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Agent_8
info: Logger[0]
INVOKE ConcurrentOrchestration: ConcurrentOrchestration_018fd151c03540daad2440299238d76a/default
info: Logger[0]
INIT ConcurrentOrchestration: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Boot/default
info: Logger[0]
START ConcurrentOrchestration: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Boot/default
Running agent tool..
info: Logger[0]
COLLECT Concurrent result [ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Results/default]: #1 / 8
Running agent tool..
info: Logger[0]
COLLECT Concurrent result [ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Results/default]: #2 / 8
Running agent tool..
Running agent tool..
info: Logger[0]
COLLECT Concurrent result [ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Results/default]: #3 / 8
Running agent tool..
info: Logger[0]
COLLECT Concurrent result [ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Results/default]: #4 / 8
Running agent tool..
Running agent tool..
info: Logger[0]
COLLECT Concurrent result [ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Results/default]: #5 / 8
Running agent tool..
info: Logger[0]
COLLECT Concurrent result [ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Results/default]: #6 / 8
Running agent tool..
Running agent tool..
info: Logger[0]
COLLECT Concurrent result [ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Results/default]: #7 / 8
Running agent tool..
Running agent tool..
info: Logger[0]
COLLECT Concurrent result [ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Results/default]: #8 / 8
info: Logger[0]
EXIT ConcurrentOrchestration: ConcurrentOrchestration_018fd151c03540daad2440299238d76a_Root/default
info: Logger[0]
MetricName: {"TotalDurationMs":"86402"}