WebSocket connection drops during peak load

Quick question, has anyone seen this weird error? with WebSocket stability. JMeter is pushing 500 concurrent connections to the Architect flow, but clients disconnect after 30 seconds.

The error log shows code 1006 without a reason phrase. This happens only when throughput exceeds 50 req/s. Our environment is GC version 24.2.

Is there a specific header or keep-alive setting we are missing? The docs mention a limit, but the numbers do not match our test results.