iAd issue
 

I am having a issue we have several iPhones and apps have iAds but some reason not appearing on iPhone 4

iPhone 5 (iOS 6) = Ads appear fine

iPhone 4S (iOS 6) = Ads appear fine

iPhone 4S (iOS 5.1.1) = Ads appear fine

iPhone 4 (iOS 6) = Ads do not appear at all

iPhone 4 (iOS 6) = Ads do not appear at all

Don't have any iPhone 3GS or older to test on....


Any idea why iAds are not appearing on iPhone 4? Anyone else having this issue? running the latest version 1.3 of mobile app.