I have custom fields set up to map from two different forms, and it doesn't work.

Bricks Builder: Subscribe form with name, email. Custom fields: utmsource, utm__campaign, utmmedium, utm__content. Slugs match exactly to FluentCRM custom fields.

Webhook set up fine. When someone subscribes, it fills the name and email, but none of the custom fields. I'm having this same issue with YouForm to FluentCRM also. Is there a secret trick to this I'm missing?