UK Payroll - Late Hire RetroPay Issues

Summary

R13 New feature is working partly for employees hired until the day before process date but not processing employees hired on or after the process date

Content

My customer pays their employees as of 21st and finalises month-end payroll, including sending RTI files to HMRC by the 21st of every month. They use payroll flows to manage their pre-payroll, payroll and post-payroll activities.  The new functionality -> late hire functionality process payroll for new starters hired until the 20th of the month. However, the late hire fails to create the retrospective events for starters on or after the 21st.