So if you open up your Pay Items window by going Payroll > Pay Items. Next, go to the leave section After that, open up each of the Leave Accrual pay items by clicking the name of the pay item. (You can narrow down which pay sites may be causing this by looking at the pay items used in the payroll) Once open, scroll down to the Link Wage Pay Item. You need to make sure that you do not have a linked wage pay item assigned to Multiple leave pay items.
If you do have multiple linked, you can remove linking by clicking the click on each pay item where needed. Once you have done this if you need to create new pay items for each individual Leave item you can do this through the Wages and Salary tab in the Pay Items menu.