Custom guest attributes dropping on Genesys Web Messaging widget init

We’ve got the embed script firing fine, but passing authenticated user data through genesyscloud.messages.conversations.createGuest keeps dropping the custom attributes. The payload looks correct on our end: { "customAttributes": { "userId": "usr_8842", "role": "premium" } }. I’m logging the network traffic and the widget just strips those keys before hitting the Genesys endpoint. Checking the console now.