Absence calc's slice date segment not recognized when paygroup change occurs mid-period

When an employee changes from Paygroup A (OPSEU) to Paygroup B (MAC) in the middle of the absence calculation period (March 1-15), the absence calc should slice/segment the entitlement.  So if the paygroup change occurs on March 6th, I would expect the absence calc to process & prorate the Paygroup A (OPSEU) accrual entitlement from March 1-5 and the Paygroup B (MAC) accrual entitlement from March 6-15.

Instead, the absence calc processes both paygroups for the full March 1-15 absence calculation period thereby erroneously accruing double the entitlement.

How do I get the absence calc to recognize the segmentation when the beginning & ending paygroups are different?