How to handle the orphan record in InventTrans?

User cancelled a PO line , but something went wrong and it created Issue=On Order , with negative Quantity in inventrans table.
User claims, he first 0 the quantity on PO line , then click on update line- delivery reminder- and clicked on Cancelled quantity. But that does not explain how it can create a -ve qty record in inventTrans table, and we were not able to recreate the issue.
Later user deleted the PO line itself. After deleting the line, the inventtrans still shows -ve QTY , with issue 'On Order' , reference to same PO number. That suggest that somehow this record is now Orphan

I understand, we should not delete records from inventrans and inventsum tables , But in this case what other options do we have?

Screen shot of inventtrans trans.