From customer:

"I am trying to map to fields that exist on both sides through the Visual connection. I cannot find the fields at all on Azure and can find on the Jira connections side when trying to add the mapping on Jira Cloud"

Visual type connection is not displaying the custom fields for adding them to mapping.
From ADO side:
Connections > Rules > Add Mapping > ADO and Jira Cloud dropdown menus do not display the system generated Custom Field named ‘Acceptance Criteria’
From Jira Cloud side:
Connections > Rules > Add Mapping > jCloud dropdown menu shows ‘Acceptance Criteria’ manually created custom field but the ADO dropdown menu still does not show ‘Acceptance Criteria’ custom field whether it is a system generated one or manually created one