Not sure if anybody still needs this information, but I have been searching for a solution to this myself. Apparently AdMob is still flawed.
The only problem is, this will stop all WebViews from running in the background. Only a problem if your app depends on this to operate.
Add to onPause()
:
new WebView(this).pauseTimers();
and to onResume()
:
new WebView(this).resumeTimers();
This came from a Google Employee who claims that they are looking into it:
https://groups.google.com/d/msg/google-admob-ads-sdk/Qu4G19NFAuI/wcNkoV0AeDUJ