startChat() CRM ID not sticking

trying to pass a customer id into the web messenger when the chat ts. i’m calling window.genesys.messenger.tChat with a customAttributes object like this:

window.genesys.messenger.tChat({
 customAttributes: { crmId: '12345' }
});

the chat opens fine but the agent doesn’t see the crmId in the transcript or the side panel. am i missing a config step on the widget side?