Symptoms
Customers sometimes get free shipping with shipping methods that they would not normally qualify for (e.g. a customer in Colorado gets UPS Ground for an order to Antarctica).
Cause
Customers who qualify for free shipping based on their cart contents will always be assigned the shipping method specified in the ShippingMethodIDIfFreeShippingIsOn AppConfig, regardless of whether or not they would otherwise qualify for that method.
Solution
Set the FreeShippingAllowsRateSelection AppConfig to true. Customers will be presented with a list of shipping methods that they actually qualify for instead of being automatically assigned one that they do not.
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