On the Team Board the Parent field is not showing on all cards. Looking at this further, only stories that have another user story as the parent will show the parent. User Stories that have a Feature as a parent are not displaying the parent field.
This is a legacy design decision that a Parent should only be User Story. A Feature is stored in the database as field Feature. In order to show the "parent" field regardless if it is a user story or a feature, you will add both the "Parent (User Story)" and "Feature (User Story)". Now when you view the cards on your Team Board, you will see the parent.