This means that the quantity and/or the price of the customer order has been changed. It can also happen when a credit invoice has been created.

Whatever you change or remove on the customer order is registered on the log date.

Whatever you add to (new row) on the order is registered on the order date.

If you use the Adjust order inflow­ button in Register customer order, all the changes you make to the order are registered on the order date. In the Order inflow procedure, you are then able to select the Grouped by order date presentation.