Could be that they did secure the license to make a Stranger Things pinball, and it will be coming out in the future - perhaps coinciding with Season 2 .. Maybe this title graphics on their website disappears after a day and we don't hear anything again about it until next year - consider this a "clue" to a future title.
As others have said, there's no way, at least that we know of, that Stern has a pinball for a TV show that came out last month almost ready to go into production. Dare I say that would be impossible?