Error validation for Date of Birth in Add Pending Worker

We have to validate the Date of Birth field for only the Employee worker type if it is empty and not for the Contingent Worker. We created a object validation rule in the Person object for the same. It's working on the "Hire an Employee", "Convert Pending Worker", and "Add a Contingent Worker" pages but it's not working on the "Add a Pending Worker" page.

Can someone please help us with the rule that will work on the "Add a Pending Worker" page.

Regards,

Swetha.