Notifications using ${URI_REF} are displaying "LINK" in place of actual ticket numbers.

For notifications using ${URI_REF} are displaying "LINK" in place of actual ticket numbers in notifications and Display field is set for desired field.

Multiple Fields on the table have the "Display" value set to true.

Check the dictionary records table that the record exists on and ensure that there is only one record that is set to display=true.  With the ${REF_URI} script it will use the display value of the record that is referenced(either in the notification or field that is specified [ex: ${task.URI_REF}]

Navigate to:

System Definition > Dictionary > search for name starts with <Table name> > ensure there is only one record with display = true