PO receipts only with headers and no lines available

Hi all,

We have a problem like user is receving the material and the IRTP concurrent is completing successfully and if we query the receipt in receiving transaction summary its saying no records available. When we queried the receipt header there are lot of receipts where the headers are alone available and no lines are there.

this is not happening for all the receipt but for some receipts. Each time user cannot query the receipt and check is it available or not. But randomly since user is aware if that he has received the quantity he tried to query it.