Web Messaging SDK guest attributes not persisting

Trying to pass custom guest attributes to the Genesys Cloud Web Messaging widget for authenticated users. The genesyscloud.messaging.init call works, but the attributes vanish once the session starts. Here’s the snippet:

genesyscloud.messaging.init({
 attributes: { userId: '12345', tier: 'gold' }
});

The logs show the payload is sent, but the conversation doesn’t pick up the data. Am I missing a step?