Approving a Leave cancelation during payroll lock

Hi experts,

I am using Fiori Approve Leave app.

During payroll lock, if the manager tries approving a new leave request, then he is thrown an error message saying "Payroll area XX is locked'. But if the manager tries to approve a cancelled/withdrawn request, it goes through. Why is this difference?

I checked the same through Tcode PTARQ, and the behavior is same. So problem is not with the Fiori app, rather with the ESS itself.

Any thoughts please?

Regards

Krishna