I looked again a bit more carefully and interestingly enough, I still see no articles at all that even mention the fact that the final result was way off from the poll numbers, much less analyze possible reasons why that was the case.  One that I did find, though, noted that its margin of error in its poll of likely voters (which showed Leppert up 47-45) was unusually high (almost six percent) because of low confidence in their determination of which voters were actually likely to turn out.  

Since, at this point, it seems no reliable sources are raising the issue of whether something like the Bradley effect occurred, I don't think there is a basis right now to include it in the article.