Node SDK WebSocket subscription timeout on conversation events

Trying to hook into real-time conversation updates using the Node SDK (@genesyscloud/notifications-api-v2). The connection establishes fine, but the subscription request for conversation:updated never returns a success payload. It just hangs until the client times out.

const notificationsApi = new NotificationsApi(client);

notificationsApi.postNotificationsEventsSubscriptions({
 body: {
 eventType: 'conversation:updated',
 filters: [
 { name: 'conversationId', value: 'valid-convo-id-123' }
 ]
 }
}).then((resp) => {
 console.log('Subscribed', resp.body);
}).catch((err) => {
 console.error('Subscription failed', err);
});

The logs show a 200 OK on the initial WebSocket handshake, but no subsequent frame for the subscription result. Checked the raw frames, nothing comes back after the sub request. Am I missing a required header or is the SDK not handling the subscription confirmation correctly?