Platform Release 12 September 2018
Before, the cart decided, based on the update actions, whether to update the product prices and tax rates. We’ve received feedback that this was unpredictable and confusing.
Therefore, the cart now updates the product prices and tax rates, along with discounts and the shipping info, on every update. No change to your code is necessary, but you may remove superfluous Recalculate update actions (if they don’t update the product data).