Google encourages mobile full page ads through Adsense. Seriously, it's just called 'Page-level ads/Vignette ads' - "Mobile full-screen ads that appear between page loads on your site and can be easily dismissed by your users."[1]

Certainly don't want anyone else getting better ad positioning than Google, no sir. That's a penalty.

[1] https://support.google.com/adsense/answer/6245304?hl=en