Is a state law error in admitting evidence prejudicial in a civil case?

Appellant argues the asserted error was prejudicial under the state law standard and also deprived him of due process." 'Ordinarily, even erroneous admission of evidence does not offend due process unless it is so prejudicial as to render the proceeding fundamentally unfair.'" (People v. Covarrubias

(2011) 202 Cal.App.4th 1, 20.)" 'Absent fundamental unfairness, state law error in admitting evidence is subject to the traditional [state law] test: The reviewing court must ask whether it is reasonably probable the verdict[s] would have been more favorable to the defendant absent the error.'" (Id. at p. 21, fn. omitted.)