I’m using AdMob’s mediation to display adds in my iPhone App.
On all versions of iOS 5, both AdMob ads and iAds display correctly at all times.
On iOS 6, AdMob ads still display correctly at all times, but below, you will see the issue I am having with iAds. Again, this is only on iOS 6. The iAd displays behind the NavBar and gets blocked/chopped off by the tab bar.
Here is the code I am using to setup my GADBannerView:
GADBannerView *tempBannerView = [[GADBannerView alloc] initWithAdSize:kGADAdSizeBanner];
self.bannerView = tempBannerView;
bannerView.adUnitID = @"OUR_ID_HERE"; //Our Mediation ID
bannerView.rootViewController = [UIApplication sharedApplication].delegate.window.rootViewController;
bannerView.delegate = self;
[self.view addSubview:bannerView];
GADRequest *request = [GADRequest request];
request.testing = NO;
[bannerView loadRequest:request];
Before Tapping Ad

After Tapping

While I did not find a solution, I decided to see if this is “my problem” or not. I replaced my GADViewBanner with Apple’s ADViewBanner and tried implementing just iAd myself and abandoning AdMob mediation.
After implementing the right delegates, the AdViewBanner displays correctly at all times! In other words… I blame something wonky with the mediation software.
If anybody has any fixes to the original issue, feel free to post. Otherwise, I will just be using iAds implemented myself instead of trying to use AdMob mediation.