The product price in order, and invoices issued based on that order, may display incorrectly if the Products detail page has incorrect or no values in the following fields: Unit of measure, Tax, Currency, Price. Check if all the mentioned fields are filled in correctly for all records on the Products detail on the order page. To ensure that the price is updated in the order, select the source price list on the Products detail once again and save the record.
By default, the tax amount is included in the product price that you enter in Creatio. To change this logic, disable the Default value checkbox in the Price includes taxes system setting.