Discretionary Disbursement payment made to employee for all already used absence

Summary:

We have a requirement for Floating holiday if the 8hr have used no disbursement , if any unused balance for the year this have to be disbursed in next year 1st payroll.

For ex: Employee applied leave on Nov 25 and got paid for that payroll, and in the 1st payroll employee got paid again for the absence 8hrs as discretionary disbursement payment.

I am sure this something wrong with Discretionary disbursement element, but unable to figure out why it triggered for an employee who already got paid in past absence.

This is not happened to every one only few people got impacted.