Google has warned multiple times to webmasters about tricking mobile users and redirecting them to another website. Google feels this is an important part of their efforts to fight spam. They know this style of trickery frustrates users and to combat that issue they will take action on these sites.
Sneaky redirects are never a good thing and Google has issued punishments for directing users to a site they didn't click in the search results. They want to apply the same to the mobile environment for users on their mobile devices. Google has made it very clear that they want the user to land on a site they expect to land on based on the snipped that Google shows.
Here is an illustration of that behavior:
We are certain that Google will release more details on this as it progresses. They have already released a Help Center article for those sites in question. This means they are prepared to start taking action - Google has always given fair notice to webmasters with any of their changes and so we expect this to be enforced very soon.