I am experiencing duplicating of item receipts against Purchase Orders only. If I search for an item receipt, it would appear once however if I pull a PO history report, at times it's duplicated or triplicated. So my accounts are not affected but a blanket Purchase Order will appear as received in full although this is not the case. 

So I have to delete the Item receipt, then reenter it using the "receive items and enter bill option". 

Can anyone advise on how to fix this problem.