Recently the Ad Performance Report and AdGroupAdService of the AdWords API were returning incomplete data from Dynamic Search Ads. The report and API service were not prepared to support this type of Ad, which resulted in the report returning an undocumented “Website Ad” type, and the service returning AdGroupAd objects with no set ad property. This issue was fixed as of March 20th. We apologize for any inconvenience this change might have caused.
Note that even though Dynamic Search Ads are no longer returned in the Ad Performance Report, their performance data (i.e. impressions, clicks, conversions) is rolled up in reports such as the Account, Campaign and Ad Group performance reports.