Phenotypical white European looking Hispanics/Latinos absolutely exist.....because Hispanic/Latino is not a race but a culture.
However, in Latin American countries, what they may consider "white" may be a few shades darker than here in the U.S....so when a mestizo looking person comes to the U.S. or even born here in the U.S. they may call themselves "white" and Hispanic, because that's how they identified in Latin America....or as Tariq said, they just prefer to be considered white.
It's a relatively arbitrary system in the first place, then take that system and integrate it into the U.S. Census Bureau classification, and it's total fukkery....there is racism connected...but there is also just the fact they have different versions of racial identification based on Hispanic/Latino culture and the particular country they come from.
White Peruvians, but notice the one with sunglasses, if she came to the U.S., would get the
treatment if she claimed to be white. That's the perfect example of grey line of "white Hispanic" in the U.S.