We're improving the way ad requests are reported in AdMob. This means you may see changes in recent request data, including a gap in past requests, as these updates are implemented. Impression and click data may also be affected.
These changes won’t affect your revenue or how ads are served in your apps, but will increase the accuracy of your AdMob reports going forward. Full historical data for the previous method of counting ad requests is still available as the
AD_REQUESTS metric within the AdSense Management API.