There’s a FAQ out for War of the Ring!
It’s not quite where they normally hide FAQs, but you can find it here.
Haven’t really started reading it yet, but any FAQ > no FAQ.
And, there it is:
Q. Does an Epic Strike affect the Hero’s fight for both a Heroic duel and the ensuing fight?
A. Yes – there’s gonna be a whuppin’.
I think this is a mistake… but at least it settles the question.