We have a work order with 480 items to work. We are finishing the items over a two week period and with several lot numbers. During one WO-I for five scrapped (failed QC) parts, the receiver mistakenly entered them as "good", then went back and undid the mistake by entering -5 in the "good" quantity. He went back and scrapped th five items...
 
Unfortunately, the quantity received as good now reads 5 units higher than actually have passed QC. I went in and looked at the stock and the lot number files and they are correct. The BOM components were properly consumed for the scapped quantity, too. It is just the number showing on the WO-I screen that is incorrect.  
 
We have seen this happen from time-to-time before and did not know what was going on, but this time we have a record of the mistaken/corrected entry of a quantity that matches the mismatch we see on the WO-I screen.
 
Any advice or fixes out there?