I am encountering a situation where the freight conditions at the item level do not carry over to the header in a consistent manner. However, if I look into the item condition and then revisit the header condition, the carried over value magically populates. I am however, unable to save the invoice with this setting. What could be driving this issue and more importantly, how do I fix it? We currently have many invoices in production that probably have the same issue. Please advice.