I don't see any reason to think there's anything structurally wrong with the way this poll was done, but the idea that Romney is winning over a fifth of Democrats, anywhere outside Appalachia, while Obama is still ahead among independents, is ridiculous.
This is a junk poll.
That said, if you believe CNN exit polls, and perhaps you should not, President George W. Bush came close to accomplishing your 'ridiculous' scenario in 2004 when he won the state's electoral votes. As stated in that exit poll, President George W. Bush won 15% of Democrats while losing independents.