Thanks. Can you give me some more info on why this happens and how to fix it. I have already checked my items list and see no settings that would affect this. I need to understand more about what causes it to be split up and how to make it not do that. Is it doing this because there is a credit line item on the invoice? (You mentioned advance payment. I use a simple credit line type entry) If so, how should it be entered on the invoice so that it does not split in the P&L?
@kpierson67
Yes, it is because you are entering a credit line item on the invoice. The proper way to record a customer prepayment is to record the prepayment by going to Customer > Receive Payments. After entering the info (customer, amount, date, etc), make sure the "Leave the credit to be used later" radio button is checked in the lower-left land corner. When you create the invoice later, click 'Apply credits' at the top of the invoice screen to apply the credit.
If you aren't actually receiving prepayments (your posted screenshot has the same date for the prepayment and the invoice, which is odd) use a sales receipt instead. Sales receipts are designed to be used when payment is received at the same time as the sale occurs.