[Admob] Hiding Banner instantly

Hi, I’m using Admob BannerAds in my game and want to release it at playstore and appstore. In android version, there’s no weird event. But, at iPhone, I dont know why but whenever I called BannerAds.Hide() don’t hide itself instantly and give delay view seconds. Making this worse, the delay become longer and longer everytime I called BannerAds.Hide().
Did this happen to you before? If so, how can I handle this?

Call Admob.Instance().removeBanner();