User noticed that the invoices synced from QuickBooks Online have a tax amount that is double the actual amount they have set as Sales Tax in QuickBooks Online.
This can happen if you have specified the Sales Tax in QuickBooks Online and at the same time also set that amount as the Main Service Tax or Main Expense Tax in Core for the project whose invoices you are getting from QuickBooks Online. Core adds the Main Service/Expense Tax on top of the invoice amount (including Sales Tax) synced from QuickBooks Online, so the tax appears to be doubled. If you are only creating the invoices in QuickBooks Online and syncing them into Core, you should not set up the main taxes in Core then so that only the sales tax synced from QuickBooks Online shows up on the invoices. That way Core does not add taxes to them again. Check the Core Help for details on QuickBooks Online Integration.