Its faulty code behind there. H1 gets underline from CSS and then, for some odd reason whole table with text-content is enclosed withing that H1. This is nonsense, H1 can only contain inline elements, not block level-elements such as table.
In cases when code doesn't follow the standards its up to browser whether to allow elements to inherit porperties from their respective parent even if the nesting is illegal.
So I'd say that IE doesn't show it "correctly" and KM or Mozilla don't show it "incorrectly" since the code is faulty in the first place. How can you display properly something thats broken in the first place?