[ci-scan] Test failure: HandleEventShutdownInitiatedByTransport fails with QuicException : The connection timed out from inactivity.

## Build Information
Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1586034
Build error leg or test failing: net11.0-osx-Debug-x64-Mono_Minijit_Debug-OSX.15.Amd64.Open - System.Net.Quic.Functional.Tests
Pull request: https://github.com/dotnet/runtime/pull/133361

KBE authoring guidance (ci-failure-scan)

- `Error Details` is for readers. The exception and stack trace are included below so the failure is understandable without opening the raw log.
- Build Analysis parses only the JSON block under `Error Message`.
- `ErrorMessage` entries are case-sensitive ordinal `String.Contains` substrings copied verbatim from the failing log.
- `BuildRetry` is false because this is a recurring test failure rather than a clear infrastructure retry case.

## Error Details

```
System.Net.Quic.Tests.QuicStreamConformanceTests.ConcurrentBidirectionalReadsWrites_Success [FAIL]
System.Net.Quic.QuicException : The connection timed out from inactivity.
at System.Net.Quic.QuicConnection.HandleEventShutdownInitiatedByTransport(_SHUTDOWN_INITIATED_BY_TRANSPORT_e__Struct& data) in /_/src/libraries/System.Net.Quic/src/System/Net/Quic/QuicConnection.cs:line 657
at System.Net.Quic.QuicConnection.HandleConnectionEvent(QUIC_CONNECTION_EVENT& connectionEvent) in /_/src/libraries/System.Net.Quic/src/System/Net/Quic/QuicConnection.cs:line 771
at System.Net.Quic.QuicConnection.NativeCallback(QUIC_HANDLE* connection, Void* context, QUIC_CONNECTION_EVENT* connectionEvent) in /_/src/libraries/System.Net.Quic/src/System/Net/Quic/QuicConnection.cs:line 806
--- End of stack trace from previous location ---
at System.Net.Quic.ValueTaskSource.System.Threading.Tasks.Sources.IValueTaskSource.GetResult(Int16 token) in /_/src/libraries/System.Net.Quic/src/System/Net/Quic/Internal/ValueTaskSource.cs:line 176
at System.Net.Quic.QuicConnection.FinishConnectAsync(QuicClientConnectionOptions options, CancellationToken cancellationToken) in /_/src/libraries/System.Net.Quic/src/System/Net/Quic/QuicConnection.cs:line 452
at System.Net.Quic.Tests.QuicStreamConformanceTests.CreateConnectedStreamsAsync() in /_/src/libraries/System.Net.Quic/tests/FunctionalTests/QuicStreamConnectedStreamConformanceTests.cs:line 80
at System.IO.Tests.ConnectedStreamConformanceTests.ConcurrentBidirectionalReadsWrites_Success() in /_/src/libraries/Common/tests/StreamConformanceTests/System/IO/StreamConformanceTests.cs:line 2516
```

This recurred after #105177 was closed. The older #107762 covered the same test hanging rather than this inactivity exception.

## Error Message

```json
{
"ErrorMessage": [
"System.Net.Quic.QuicException : The connection timed out from inactivity.",
"at System.Net.Quic.QuicConnection.HandleEventShutdownInitiatedByTransport"
],
"ErrorPattern": "",
"BuildRetry": false,
"ExcludeConsoleLog": false
}
```

Agentic workflow metadata (ci-failure-scan)

Workflow artifact: ci-failure-scan
Artifact kind: kbe-verification
Verified match count: 1 hit in the failed test result

> [!NOTE]
> This issue was generated by GitHub Copilot.

### Known issue validation
**Build: :mag_right:** https://dev.azure.com/dnceng-public/public/_build/results?buildId=1586034
**Error message validated:** `[System.Net.Quic.Tests.QuicStreamConformanceTests.ConcurrentBidirectionalReadsWrites_Success System.Net.Quic.QuicException : The connection timed out from inactivity.`]
**Result validation:** :white_check_mark: Known issue matched with the provided build.
**Validation performed at:** 9/7/2026 6:15:41 PM UTC

### Report

|Build|Repository|Test|Pull Request|
|---|---|---|---|
|[1586034](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1586034)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamConformanceTests.ConcurrentBidirectionalReadsWrites_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1586034&view=ms.vss-test-web.build-test-results-tab&runId=43766744&resultId=194484)|dotnet/runtime#133361|
#### Summary
|24-Hour Hit Count|7-Day Hit Count|1-Month Count|
|---|---|---|
|0|1|1|

### Known issue validation
**Build: :mag_right:** https://dev.azure.com/dnceng-public/public/_build/results?buildId=1586034
**Error message validated:** `[System.Net.Quic.QuicException : The connection timed out from inactivity. at System.Net.Quic.QuicConnection.HandleEventShutdownInitiatedByTransport`]
**Result validation:** :white_check_mark: Known issue matched with the provided build.
**Validation performed at:** 9/9/2026 5:59:06 PM UTC

### Report

|Build|Repository|Test|Pull Request|
|---|---|---|---|
|[1586034](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1586034)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamConformanceTests.ConcurrentBidirectionalReadsWrites_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1586034&view=ms.vss-test-web.build-test-results-tab&runId=43766744&resultId=194484)|dotnet/runtime#133361|
#### Summary
|24-Hour Hit Count|7-Day Hit Count|1-Month Count|
|---|---|---|
|0|1|1|

### Report

|Build|Repository|Test|Pull Request|
|---|---|---|---|
|[1596331](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1596331)|dotnet/runtime|[System.Net.Quic.Tests.MsQuicTests.WriteTests](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1596331&view=ms.vss-test-web.build-test-results-tab&runId=44072228&resultId=195431)|dotnet/runtime#133893|
|[1596084](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1596084)|dotnet/runtime|[System.Net.Quic.Tests.MsQuicTests.Read_ConnectionAbortedByUser_Throws](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1596084&view=ms.vss-test-web.build-test-results-tab&runId=44065282&resultId=194569)|dotnet/runtime#133896|
|[1595682](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1595682)|dotnet/runtime|[System.Net.Quic.Tests.MsQuicTests.BigWrite_SmallRead_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1595682&view=ms.vss-test-web.build-test-results-tab&runId=44057048&resultId=194462)|dotnet/runtime#129220|
|[1594630](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1594630)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamConformanceTests.ReadWrite_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1594630&view=ms.vss-test-web.build-test-results-tab&runId=44022456&resultId=192658)|dotnet/runtime#133659|
|[1594658](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1594658)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamTests.ReadWrite_Random_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1594658&view=ms.vss-test-web.build-test-results-tab&runId=44022440&resultId=194875)|dotnet/runtime#133819|
|[1594598](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1594598)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamTests.ReadWrite_Random_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1594598&view=ms.vss-test-web.build-test-results-tab&runId=44020280&resultId=193106)|dotnet/runtime#132827|
|[1592881](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1592881)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamTests.ReadWrite_Random_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1592881&view=ms.vss-test-web.build-test-results-tab&runId=43971334&resultId=171492)|dotnet/runtime#132721|
|[1592345](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1592345)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamTests.ReadWrite_Random_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1592345&view=ms.vss-test-web.build-test-results-tab&runId=43956870&resultId=192085)|dotnet/runtime#133599|
|[1591884](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1591884)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamConformanceTests.ReadWrite_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1591884&view=ms.vss-test-web.build-test-results-tab&runId=43942486&resultId=201631)|dotnet/runtime#133651|
|[1591715](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1591715)|dotnet/runtime|[System.Net.Quic.Tests.MsQuicTests.DoesNotSendIPAsSni](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1591715&view=ms.vss-test-web.build-test-results-tab&runId=43938480&resultId=182260)|dotnet/runtime#133639|
|[1589516](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1589516)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamConformanceTests.Read_Eof_Returns0](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1589516&view=ms.vss-test-web.build-test-results-tab&runId=43875934&resultId=170512)|dotnet/runtime#133463|
|[1589165](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1589165)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamTests.ReadWrite_Random_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1589165&view=ms.vss-test-web.build-test-results-tab&runId=43868006&resultId=127236)|dotnet/runtime#132953|
|[1588569](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1588569)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamTests.WriteAbortedWithoutWriting_ReadThrows](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1588569&view=ms.vss-test-web.build-test-results-tab&runId=43847086&resultId=194822)|dotnet/runtime#133474|
|[1586034](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1586034)|dotnet/runtime|[System.Net.Quic.Tests.QuicStreamConformanceTests.ConcurrentBidirectionalReadsWrites_Success](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1586034&view=ms.vss-test-web.build-test-results-tab&runId=43766744&resultId=194484)|dotnet/runtime#133361|
#### Summary
|24-Hour Hit Count|7-Day Hit Count|1-Month Count|
|---|---|---|
|3|13|14|

Start with System.Net.Quic.Tests.QuicStreamConformanceTests.ConcurrentBidirectionalReadsWrites_Success in QuicStreamConnectedStreamConformanceTests.cs and inspect QuicConnection.cs around lines 657, 771, and 806. Reproduce the failure on the net11.0 macOS leg, then determine and address the recurring inactivity timeout so the conformance test passes reliably.

Written by the indexing model from the issue text.