[Bug] chip-tool interactive server hangs during ble-wifi commissioning — WebSocket closes with 1011 keepalive ping timeout, aborting FirstChipToolSuite (TC-ACL-2.1)

Describe the bug

When running FirstChipToolSuite (first test case TC-ACL-2.1) on the Matter Test Harness, the run fails during the Commission DUT setup step.

After the operator confirms the DUT is in commissioning mode, the chip-tool interactive (WebSocket) server produces no output at all for ~2.5 minutes, and then the Test Harness closes the WebSocket with:

Test Suite Error: Error occurred during setup of test suite.FirstChipToolSuite. sent 1011 (internal error) keepalive ping timeout; no close frame received

The whole run is aborted (TC-ACL-2.1 → CANCELLED, suite → ERROR).

This does not look like a clean commissioning failure — a clean failure would emit chip-tool error logs and keep the WebSocket alive to report the result. Instead the process appears to hang / become unresponsive:

No chip-tool log lines are emitted between "User chose DONE" (01:32:07) and the keepalive timeout (01:34:37).
On teardown, pkill -SIGTERM on chip-tool does not stop it (Could not get exit code after pkill command ...).
The Docker API call then times out (UnixHTTPConnectionPool ... Read timed out. (read timeout=60)), forcing the container to be stopped.

Steps to reproduce the behavior

1. Set up the Matter Test Harness (TH v2.16-beta1+summer2026, SDK SHA 9dc6ceb).
2. Configure the DUT: discriminator=3840, setup_code=20202021, pairing_mode=ble-wifi.
3. Configure the WiFi network (ssid=TestWiFi).
4. Start FirstChipToolSuite (test case TC-ACL-2.1).
5. At the prompt "Make sure the DUT is in Commissioning Mode", click DONE.
6. Observe: chip-tool stays silent for ~2.5 min, then the WebSocket is closed with a 1011 keepalive ping timeout and the suite aborts.

Expected behavior

Commissioning of the DUT over ble-wifi should complete successfully (or, on failure, chip-tool should emit a clear commissioning error and keep the WebSocket connection alive so the Test Harness can report the failure gracefully instead of timing out). chip-tool should also terminate cleanly on SIGTERM during teardown.

Log files

UI_Test_Run_2026_07_07_09_32_01.log

PICS file

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Screenshots

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Environment

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Additional Information

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Start by reproducing FirstChipToolSuite test case TC-ACL-2.1 with the provided UI_Test_Run_2026_07_07_09_32_01.log as a reference, focusing on the period after “User chose DONE.” Investigate the chip-tool WebSocket hang, 1011 keepalive timeout, and failed pkill/Docker teardown; done means commissioning reports success or a clear failure while the WebSocket stays alive and chip-tool terminates cleanly.