The pay period end date is typically used as the pay run ID for on-cycle biweekly and monthly payrolls. On occasions where two pay end dates are the same, the pay run ID of one of them is changed so the run IDs are unique. 

The biweekly payroll that will run this Friday has pay period end date of June 30, 2018, which is also the monthly PPE date, so its run ID has changed. The PPE date for biweekly payroll remains 6/30/18 and the run ID is now 6/29/18.