When a custom field stores a constituent ID as its value, the relationship is only visible on the record containing the custom field. Make this relationship visible from both sides.

Example: An Appeal has a custom field whose value is a constituent ID. While the link is available on the Appeal record, it is not visible when viewing the related Constituent. Surface these linked custom fields on the Constituent record as well, allowing users to easily see all records that reference that constituent without needing to search through other record types.