Retro entries on state pension not calculating correctly

An employee was moved to another position effective 3/30/26. The changed created a retro process on their 04-17-26 pay date (PPSD 03-21-26 thru PPED 04/03/26) The retro seemingly went back to the 04/03/26 pay period (PPSD 03-07-26 thru PPED 03-20-26) and recalculated the county pension processed on 4/3/26 and reversed it on 4/17/26 additionally processing the deductions for the new state pension plan. The client suggests that the negative retro should not have been taken back on 4/17/26. We think the issue is with mid-period change effective 3/30/26 and the configuration on the county and state pension plans. Has anyone had this happen?