User is trying to map activity and expense records between CORE and QuickBooks Online, but some of the items like COREExpenseAmt and COREServiceAmt always remain unmapped on the QuickBooks Online side. Why don't these items map to any CORE record?
When you send invoices to QuickBooks Online for the first time, CORE also sends some adjustment items along with them. You can see these items like COREExpenseAmt and COREServiceAmt in the QuickBooks Online > Sales > Products and Services screen. CORE uses these items to represent some specific details on QuickBooks Online invoices. For example, COREServiceAmt represents the summarized time on QuickBooks Online invoices when you choose to send invoices with summarized items. Similarly, the adjustment item COREInvDiscount represents the discount you apply to your invoices in CORE on the corresponding QuickBooks Online invoices. As these are adjustment items, they do not map to any CORE record and always show up as unmapped items on the Record Mappings screen under Activity and Expense Items on the QuickBooks Online side.