Not sure if this is AdMob or Corona bug.
After the interstitial is shown, the banner will not be shown anymore.
Here is what I get in the log:
<Warning>: <Google:HTML> You are currently using version 6.12.0 of the SDK, which doesn’t officially support iOS 8. Please consider updating your SDK to the most recent sdk version, 6.12.2, to get iOS 8 support, including a fix for smart banner rendering in landscape mode. The latest SDK can be downloaded from http://goo.gl/iGzfsP.
As you can read, Google admits a bug for landscape mode, also this SDK does not support iOS8!
Using latest build: 2014.2511
Corona Labs, please fix this ASAP.
Regards,
Damir