Since the most recent bundle update, some of our customers will notice that the taxable checkbox on the customer card began to exempt customers if unchecked.
The only resolution to this issue is to update your customers to properly reflect their exempt status on the customer card. If you want the client to be tax exempt, uncheck the box. If you want the client to be taxable, leave it checked. If you need to change the checkbox for a large number of customers, mass update is recommended.