The Google mobile interstitial ad penalty is just around the corner now.
What constitutes a mobile interstitial that would trigger the penalty is something Google has been answering for months now.
Recently, Kristine Schachinger asked Google's John Mueller if it is only from search results page to the landing page and yes, it is. Google is only looking to see if a mobile interstitial is being triggered after the searcher goes from Google to your page. What they do after the page, Google is not currently looking at.
So if you don't have a mobile interstitial on the SERP to the page but you do from a page to another page - you are fine.
Forum discussion at Twitter.