To recreate this issue: 1. Set up the Point of Sale (POS) system preference --Enable the "EnablePointOfSale" pref --Enable the "UseCashRegisters" pref --Set up a cash register --Enable the "RequirePaymentType" 2. Go to a patron account and create a manual invoice - save and pay. 3. Make or leave the amount tendered as the charged amount so that you don't have to provide any change. Then attempt to confirm the transaction without adding a payment type. --"This field is required." will pop up next to payment type. 4. Now change the amount tendered to a higher amount so that you have to provide change to the patron. Then attempt to confirm the transaction type without adding a payment type. --"The amount collected is more than the outstanding charge" pop up box will appear confirming the change you will provide to the patron. Select "Yes". This will cause a 500 error to occur or in some library cases it will go through without providing an error. The completed transaction will not include a payment type and can cause issues with accounting.