The Service Portal List Page / Data table widget is missing values for reference fields when the user does not have access to the referring table. This is caused after the HR scoped app plugin is activated.

1) As administrator, activate the HR scoped application.

2) As an ess user, create new incidents.

3) Impersonate the admin user and populate the Assigned To field for the incidents created in previous step.

4) Impersonate the ess user and configure the incident list layout by adding the Assigned To column. Here (on incident_list.do) the Assigned To field value is correctly displayed.

5) Go to the url: <instance>/sp?id=list&table=incident&view=default

Notice the Assigned To field is blank.
If you enable Debug Security, and access the same SP url, you will see the Assigned To field value is displayed.

This is expected behaviour. Service Portal currently will not show a reference field display value in a list to a user without ACL read access to the record that is the target of the reference. E.g., if assigned_to is Beth Anglin, and a user does not have read access to Beth's sys_user record, then her name will not show up in the list.

As a  workaround, grant read access to the target reference table to users who need to see the display value in a Service Portal list.