Node.js Kafka consumer dropping Genesys Cloud analytics events

Trying to pipe Genesys Cloud analytics WebSocket events into a local Kafka topic using a simple Node.js consumer. The connection holds, but I’m only getting about 10% of the expected events, and the payload structure looks truncated compared to the docs.

ws.on('message', (data) => {
 producer.send({
 topic: 'genesys-analytics',
 messages: [{ value: data.toString() }]
 });
});

Am I missing a specific header or subscription filter in the initial WebSocket handshake?