We have a reproducible scenario in which applicable taxes (based on shipping address) are not being consistently charged in FC v2.0. Taxes do get calculated, but then a few basic steps result in no taxes being applied. Not good!
1. Ensure store is configured for taxes in specific region, associated to category in use. (e.g. CA, NY, etc)
2. Browse to product page, ensure fresh
fcsid. (store URL to-be-whispered)
3. Add shippable product to cart.
4. Click "Proceed to Checkout"
5. Fill out Shipping ZIP Code within taxable region (e.g. 84101)
6. Watch as Tax is calculated and applied, increasing the Order Total.
7. Click "Use a different billing address." checkbox
8. Fill out Billing ZIP Code outside the taxable region (e.g. 83704)
9. Watch as Tax disappears and Order Total is decreased.
10. Uncheck "Use a different billing address." checkbox
11. Watch as Order Total is not affected, tax is not calculated or re-applied.
This appears to be an order of operations issue, combined with lack of proper handling for certain events. It seems the way to work around this issue is to ensure that "Shipping ZIP Code" is entered last. That seems to trigger the necessary calculation and apply the tax. Unfortunately, it's not a realistic solution to expect each customer to stumble upon.
I'm sure I could rig some custom code to work around this, but this seems important enough a bug that it should be fixed at the source. Hoping the FC team can verify?