There's a simple explanation why this poll is too pro-Obama - the sample. This is with 2012 turnout better for Democrats than 2008, which is highly unlikely.
I'll repeat, national polling has very odd swings (even party ID) and polling hardly ever exactly matches what the electorate will be like, especially not this early. I'm not saying that the poll isn't too high for Obama, but the sample isn't pre-determined, party ID is asked about during the call and after the presidential race is asked about, which is more consistent with an odd swing.
