A big surprise in the California June primary was how badly Democratic congressman Scott Peters did. In 2012, Democrats lost the CA-52 primary by 3.5%. Scott Peters had a narrow 2.4% win in November. Peters entered this primary as an incumbent. So he would've been expected to do as well as he (and other Democrats) did last year. Instead, he lost to the Republicans by 15.4%. That's a lot to overcome and even would've been in 2012. Some people started to write Peters' political obituary. A little after the primary, KGTV-TV San Diego commissioned SurveyUSA to do a poll shortly after the primary and their results confirmed the primary result. They had DeMaio up by 7%. That's a terrible narrative for an incumbent, especially this far from election day.
House Majority PAC, a Democratic SuperPAC, released a poll that contradicts the primary and independent poll results. They have Peters leading DeMaio by 5%. The party ID breakdown in the poll is Republicans +8, a believable breakdown for the district. What's not believable is Peters taking 16% of the Republican vote and winning DTS/other by 24% isn't. In the SurveyUSA poll, DeMaio won independents by 20%. Republicans likely won independents by more than that in the primary. I don't find the survey results believable but I do find them understandable. After Peters bombed in the primary and SurveyUSA had him down 7 he needed a poll saying he's winning. Here it is.