I have this weird problem where I can't change a customer's Customer Tax Class through the admin interface. It keeps jumping back to Retail customer.
So when I select a different Customer Tax Class and press save, it just stays at Retail customer.
Even when I update the customer's Customer Tax Class through the database with an SQL query (shown below), it works and does change the Customer Tax Class of the customer, but when I go back to the interface, and press the "Save Customer" button (in case I would like to edit some other information) it will jump back to the wrong Customer Tax Class, "Retail Customer".
UPDATE `customer_entity` SET tax_class_id = MY_TAX_CLASS_ID WHERE entity_id = CUSTOMER_ENTITY_ID
I checked the Customer Group settings, and for that Customer Group, I set the default Customer Tax Class to the one I actually want, but even then it keeps jumping back to Retail Customer.
I haven't set up this installation so a previous manager might have set up a limitation somewhere? I don't know.
Thanks in advance, this stackexchange board has been of great help trying to unravel the enigmatic spaghetti which is Magento.