A while ago I moved to Medford Oregon for a couple of years and the hostility towards Californians was real. Someone I know moved to Southern Oregon recently and it's a little better, primarily because there are a lot of Californians there enjoying great property values and no sales tax.
Where I moved in the Pacific North West, the most hostility comes from the people who moved here 15-20 years ago, often from California too. Although, some of them are pretty chill. Most of the people with deep roots are pretty chill too, but I have run into a amall handful of extra grumpy people.