Incorrect Qty on SO

So rebuilding sort files typically cleans this up, but we have an item code showing a warehouse having a qty of 8000 on Sales Order, but as far as we are aware (and as stated on the 'Orders' tab in item maintenance, the item is on 2 sales orders for a total of 3000.  

Has anyone ever come across this situation where rebuilding sorts doesn't clear it up?  Thanks!