PR 's are reopening in ME55 even sales order status is complete

Dear Sir,

My scenario is when i run MRP new PR 's are getting generated even though the sales order status shows as complete.

I tried deleting as well as marking PR as closed,Which ever PR  I delete or close will not appear in ME55,but if i run new MRP by MD03 ,new PR will get generated,even when sales order is complete.

Please help how can I stop this creation of new PR when Sales order status shows complete.

Thanks