Princess Mononoke was shown this week and it was not the dubbed version. I was confused though why the credits appeared to be the ones from the dubbed version crediting the American voice actors rather than the Japanese ones. Can someone explain this to me?

same thing on the UK-release DVDs of other Ghibli films.
Seems like the visual print (?) for both soundtracks (Japanese & English language) is the same, including the credits.

This is what confuses TV companies (incl C4/F4) when they show these films, they publish on their listings the Western voice actors as the stars even when the original lang version is used.