Hi JDE folk, it is a well know mistake. Users (JDE beginner) have the reflex to enter signed quantities for credit order whereas it is automatically reversed by the line type definition (LNTY) during the line validation, involving an ordered positive quantity and then, stock issuing instead of stock entering.
My company has developed a program to block the order header if one of the lines selected by the version is successful (similar to the R42640 but based on F4211). So, we have added a version of this program in the RMA process in charge of detecting if an input line has a positive quantity and hold the order (Hold code in P.O) in order to intervene by changing the sign of the offending line. Unfortunately, this program does not exist in standard but I systematically propose it to my customers because it is useful in many other control cases.