Having an issue with some ads not showing on Android devices despite the AdView's ad listener suggesting the ad was loaded (onAdLoaded called). The same ad units display correctly in iOS and on a web test page using JavaScript and the ads are visible on those platforms as expected.
I was able to reproduce the issue using the AdMob BannerExample app to attempt to reduce the likelihood of this being an app-related problem and see the same behavior, where onAdLoaded is called but there is no visible ad. When I use the test ad unit id "ca-app-pub-3940256099942544/6300978111" I see the test ad of the same dimensions (medium rect size) as expected in the view. I'm seeing the same behavior on multiple Android devices with multiple versions of Android, so I don't think it is anything version specific.
Is there someone on the Ads SDK team I can share the ad unit ids and/or application logcats with to try to understand why this is happening? Thanks!