There is code in the planning function that if there are any item ledger entries against a production order, planning will treat the order as planning flexibility none. The result of this is that if the demand date is before the supply date (dales order pulled in or prod order moved out) planning will ignore the released order and suggest a new order resulting in an over-supply.
For example I have a production order for 1000 pieces due June 1 related to a sales demand for 1 piece due June 1 and I consume some of the raw material. If for some reason, the sales order is moved to May 31st, planing will now ignore the production order and suggest a new order for the sales order demand (if the multiple is 1000 it would be for the multiple). It will never suggest a change or cancel to the original order since it views it as planning flexibility = None.
Many companies have thousands of planning messages and to not even present and exception message that there is a supply / demand imbalance is very dangerous and several of our customers have ended up with thousands of dollars in mistakenly ordered components.