Dear Glen,
Shortcodes in custom fields aren't normally parsed. But you can add the following line to functions.php for processing them. If your field slug is test, use:
add_filter('wpcf_fields_slug_test_value_display', 'do_shortcode');
Replace test with the slug of your custom field. Or you can do it for all fields with:
add_filter('wpcf_fields_value_display', 'do_shortcode');
Please let me know if you are satisfied with my answer and if I can help you with any other questions you might have.
Regards,
Caridad