When closing a PO with unreceived items, the message says first "you have $x amount of items that have not been received" which I expect, but then it says "YOu have $Y that has not been invoiced" when that amount has been invoiced and posted and is no longer in RNI.  
I tried zeroing out the line item before closing and that didn't fix the problem.  The solution is to close it anyway, but why is it saying that?  It sends my AP person into a highly agitated state.  Fortunately we rarely only partially receive a PO and then try to close it.  Is there a best practice for this that I don't know about?