Interstitial ads are full-screen pop-up ad|ads that cover the interface of their host app shown at natural transition points in the flow of an app
The pop-up is requested by an action of the user. This way, the pop-up is not blocked.
This is an authorized flow of interstitial from the IAB.
Display: at natural transition points in the flow of an app, such as:
Options
Choice: when an app shows an interstitial ad, the user has the choice to: