If only 1 PRSI week is generated for an employee in a fortnightly pay group, this is because the week by week calculation option is selected under part time PRSI calculation method.
To resolve this, follow the steps below in Back Office.
Click CorePay then click Employee.
Click Advanced Employee Features then click Amend Employee Sundry Profile.
In the Employee Reference field, to select an employee, click the list
icon.
Press Tab on your keyboard.
In the Part time PRSI Calculation Method field, disable the Week by Week Calculation option.
Click the save
icon.