Hello,
This is a Northern Flicker. They do often have a bit of white below the color, although not often as distinctive as yours. With that said, it is not unexpected and you can find other examples of similar plumage flickers on eBird. In particular when the plumage is fresh or worn (bird grown new feathers and replace old ones every year) the feathers can appear to have extra colors or be washed out. Also there is genetic variation that creates some variability so bird books are a model but can not capture all the variation that may be encountered in the wild.

You can learn more about Northern Flickers here: https://www.allaboutbirds.org/guide/Northern_Flicker/overview#

You can see more pictures of other flickers here: https://media.ebird.org/catalog?taxonCode=yesfli&sort=rating_rank_desc&mediaType=photo