Nidalee spear does not reveal Wukong????

Yesterday, I hit Wukong with a spear before he cloned and Nidalee's passive did not keep him revealed. At the time I said okay, so that does not work. I can deal with that. Then, later on in the game, I hit him not once, but twice, after he cloned and the spear did not reveal him. I know his clone makes him stealth and it doesn't make him appear off the map for a time such as LeBlanc's passive or Master Yi's Q. SO, I was wondering if this is an oversight or a bug of some sort? Thank you in advance for any info on this.