On March 19, 2018, we are updating how AdNetworkType1 and AdNetworkType2 columns report zero impression rows related to video networks.

Currently, if you request AdNetworkType1 or AdNetworkType2 columns and request zero impression rows by setting the includeZeroImpressions flag to true, you get back zero impression rows for YOUTUBE_SEARCH and YOUTUBE_WATCH values only if you target these networks in your Advertiser account. After this change, we will always return zero rows corresponding to these network types irrespective of whether you advertise on these networks. Other network types are not affected by this change.

This change makes the behavior of YOUTUBE_SEARCH and YOUTUBE_WATCH network types consistent with the behavior of other network types. Once this change goes live, you may start seeing a higher number of zero impression rows than what you see today when requesting AdNetworkType1 or AdNetworkType2 columns along with zero impression rows.

If you have any questions about these changes, post them in our developer forum.
 - , AdWords API Team