The refund will post to the same currency as the original charge was charged. It doesn't make a difference that you have a US issued card.
It indeed did. The issue is that I lost some money, presumably because N euros was worth more $$ the day the charge posted than the day the refund posted. My question is whether that is simply a risk one bears when buying a refundable ticket that gets charged in a foreign currency, or whether I have any recourse.