have u submitted your adsense id to hubpages?. If yes, they will be including in the source code which will look like this, ca-pub- ****** . But also, there will be their id like channel id or something pub****** .
So, I'd like to tell you to check that. Once i contacted them directly for this issue. They'll be running their own also, so that 60% revenue is ours and 40% is theirs.
Hope that helps...