Quick question about WebRTC WebSocket drop in JMeter

Quick question about WebSocket stability during load tests.

Running JMeter 5.6.2 from Asia/Singapore. Trying to simulate 50 concurrent WebRTC softphone sessions. Connections establish, but after 30 seconds, the WS closes with code 1006. No 429s or 503s.

Is there a specific header or keep-alive setting missing in the HTTP Request sampler for the media handshake? The Architect flow is basic inbound routing.