Symptoms
Approval tab is missing from HR case record
Release
Kingston
Cause
In approver related list "Omit if empty" checked box was checked.
As a result for the HR payroll case which does not have any approvers, the approver tab itself was not showing.
Resolution
Uncheck the checkbox:"Omit if empty"
This will enable to show approver tab always.
Additional Information
Please check the following doc link for details: