I've never experienced H2 to be larger than H1 in such usage, but rather the same size. Are you sure there aren't any CSS affecting your result?
From a stackoverflow reply:
Why h1 and h2 are same?
This is by design is because browser manufacturers think/agreed, that beneath web editors, producers and developers the is commonly treated as the visual more important heading and headings in the content documents should then ideally start with . That is why font-size is not default bigger inside , , , tags.