POSTING ERRORS LINKED TO LINES AFTER LINE 46000

We have a problem that intermittently appears after posting purchase order receipts (of longer then 46 lines). Here is the scenerio: a)Receiving is done on purchase order. Items received came from lines after Line 46000 b)Posting finished with no error messages c)Upon review we noticed that the PO was not updated (ie QTY received not updated for reciept). The reciept was actually created which we can print out but all lines after 460000 did not get updated. All correct information is in the item card and ledger entries. d) Also along with this we got a situation where a phantom receipt was created using some of the line items from the PO above and using some unrelated vendor header. This is ~ the 6th time this has happened and everytime with items after line 460000 Has anyone come across this before? Please help… Thanks Jim